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The planets are joined by our Moon on these dates: ...
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The planets are joined by our Moon on these dates: ...
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Total lunar eclipse December 10.
(In the early evening, imagine all the following still being further est.) Looking at the sky in the late evening around 11 pm, prominent constellations and stars are the Big Dipper (part of Ursa Major) high in the northeast and the Little Dipper high in the north, Cygnus with Deneb, Lyra with Vega and Aquila with Altair now low in the northwest. These three stars form the summer triangle: it's perhaps comforting that in Alaska we can see this summer triangle all winter along, albeit near the horizon. Cassiopeia appears overhead, in the zenith, Pegasus' square/diamond to the upper right of the very bright Jupiter in the southwest. In the east Gemini with Castor and Pollux, Cancer with the Beehive cluster and Leo have risen, following Orion with red Betelgeuse and blue Rigel which are now quite high in the southeast (that's why I chose the late evening for my description). Auriga with Capella and Taurus with Aldebaran and the Pleiades star cluster appear now high in the south.
Mercury and Venus are too close to the sun to be viewed this month.
Mars and Saturn rise after midnight and can be seen in the south and southeast, joined by the half moon on Nov 18 and the crescent on Nov 22, respectively.
A very bright Jupiter can be seen all night long, seemingly traveling east to west, pairing with the full moon on Nov 8 and 9.
Uranus and Neptune can be seen low in the southwest early in the evening. Google good sky charts and use good binoculars. The gibbous moon leads the way on Nov 5 and 3, respectively.
This is the next in my series of explaining and instructing some of the most misunderstood topics: this time it’s the moon’s phases.
Throughout the month we can see more or less of the moon’s disk – well, we would if it wasn’t so cloudy on the Kenai. At the beginning of the lunar cycle it’s the crescent on the lower right of the moon’s disk, then half on the right, gibbous on the right (all visible in the evening, then progressing into late night), full (all night long), gibbous on the left, half on the left, crescent on the lower left (visible from late night on but then only at pre-dawn), all of these phases for a few days each, combining to a total of 29½ days.
To produce these varied phases, basically two things are required: one is a light source (the sun of course); the other is us on Earth observing the moon.
The sun illuminates always the half of the moon that is facing it and leaves the other half dark.
As the moon orbits Earth, we get to see different amounts of each of the moon’s lit-up and dark halves.
For the moon’s phases demonstration use a semi-darkened room, an overhead projector (or a bright lamp), a globe of the Earth, and a whitish ball somewhat smaller than the globe. Position the globe about eight feet away from the sun (the projector), and have another person hold the moon (the whitish ball) about three feet from Earth and in between but a little lower than Earth and Sun. (The distances are not to scale but the projector’s light wouldn’t help you if you had to place it a football field’s length away just to keep the real distance scale.)
For this and the following notice that half of the moon is always lit and the other half is always dark. But it’s what we see from Earth that makes the moon appear different as it goes through its phases.
Always position yourself on the side of the Earth opposite from where the moon is – that way it’s as if you’re looking at the moon from Earth.
Now look at the moon and notice that you only see darkness. (This is called the new moon because it’s at the beginning of a new lunar cycle of phases.) In this position you also need to shield your eyes, so that you don’t stare into the sun. By the way, the moon is placed below Earth and sun to avoid a solar eclipse – as is usually the case anyway.
Next have the other person move the moon about 45 degrees counterclockwise in its orbit. You likewise move along to be again opposite from where the moon is. Now you should see just a sliver of the moon’s lit-up half on the right hand side – and that’s the crescent moon. (The first image shows that Earth and moon's sides facing the sun are lit. The second image shows that from the viewpoint of Earth, only a sliver of the moon's lit-up half can be seen.)
Keep having the moon (and yourself on the opposite side) moved by 45 degrees and you see that you see more and more of the moon’s lit-up side – half, gibbous (both on the right hand side), full. At the full moon phase make sure to have the moon above Earth and sun in order to avoid a lunar eclipse – as is usually the case anyway. Keep moving along and you see less and less of the moon’s lit-up side – gibbous, half, crescent (all on the left hand side), back to new.
And that's the explanation for the moon’s phases – not that simple perhaps but it's the correct one.
By the way, the moon appears just as often during daylight as it does during the night. But we don’t usually pay attention to it because its phase is more crescent, it appears relatively close to the bright sun and it competes with a bright sky as well.
Postscript: there was no mention of any shadows in this explanation – because there aren’t any. The only time shadows come into play is during solar and lunar eclipses, such as the total lunar eclipse next month, Saturday, December 10, in the pre-dawn hours, visible from all of Alaska.
Post-postscript: there was no mention of the far side of the moon. We see only half the moon’s surface because it rotates exactly once while it orbits exactly once, hence we always see the same side. Both the Earth-facing and the Earth-facing-away sides go through day and night and therefore the far side is not to be confused with the dark side (except for the bottoms of many small craters near the moon’s poles, no large scale parts of the moon’s surface are permanently dark).
Compared to September the sky shifted somewhat towards the east with Bootes setting in the northeast; its brightest star Arcturus can be seen in the early evening on the northeastern horizon. Prominent constellations and stars are the Big Dipper low and the Little Dipper high in the north, Cygnus with Deneb, Lyra with Vega and Aquila with Altair still high in the west. These three stars form the summer triangle: it's perhaps comforting that in Alaska we can see this summer triangle all winter along, albeit on the horizon. Cassiopeia appears overhead, in the zenith, Pegasus' square/diamond to the right above the very bright Jupiter in the southeast. Late in the evening Orion rises with Betelgeuse and Rigel in the east, following Taurus with Aldebaran and the Pleiades star cluster.
Mercury appears close to Venus in late October but it's very close to the horizon.
Starting in late October Venus will shine brightly in the evening all winter long. It is then also near a waxing crescent moon on October 28.
Mars rises after midnight. To quote this month's issue of Sky & Telescope, "Mars in in the middle of M44, the Beehive cluster in Cancer - a fine view in binoculars and telescopes, and a great photo opportunity." Mars is joined by the waning crescent moon in the morning of October 21.
Jupiter can be seen all night - due to its brightness it's the first object that catches the eye anyway. The virtually full moon pairs up with Jupiter on October 12.
Saturn is in (upper) conjunction with, i.e. behind, the sun and can thus not be seen.
Uranus in Pisces and Neptune in Aquarius can be seen for most of the evening; but since they are faint, you would need a good sky chart (see nakedeyeplanets.com) and strong and stable binoculars.
Starting with this column I want to adapt my "Very Important Topics" unit from my KPC astronomy class as a teaching unit for anybody who would like to use it. And I start out with the most misunderstood topic: the reasons for the seasons.
If you want to get more or less heat from a campfire, you would move closer or, respectively, further away. But it's not that simple for Earth and doesn't apply because Earth maintains the same distance to the sun throughout its orbit. Therefore its warm and cold seasons must be caused differently.
So here are the explanation and instructions to teach seasons. Using four phrases those reasons are tilt-of-axis and orbit-around-sun which produce different-daytime-lengths and different-height-of-sun throughout the year.
For the seasons demonstration use a semi-darkened room, an overhead projector (or a bright lamp), a globe of the Earth (delivered crooked by the manufacturer, i.e. at the correct axis tilt), and a Lego figurine. Position the globe about four feet away from the sun (the projector) with the Earth's axis, i.e. its north pole, pointing towards the sun; and carefully note as well towards which wall the axis is pointing in the room you're in. As a trial run for the Earth's orbit, move it counterclockwise around the sun - make sure to maintain the same distance at all times and the same orientation, i.e. pointing the axis towards the same wall, as if the axis was fixed in space (which it is: this is equivalent to the same point in space which is Polaris, the North Star).
Back at the original position, with the (northern) axis fixed pointing towards the same wall and again towards the sun, explain why it is summer in the northern hemisphere: position the figurine in North America, Europe or Asia. Rotate the globe slowly and show that between sunrise and sunset (marked by the terminators, i.e. divisions between light and darkness on the globe) the figurine is on the daylight side of the Earth for a long time. Imagine yourself being the figurine and notice that the sun appears quite high in the sky; a drawing with a horizon and the cardinal directions may help: the sun rises in the northeast, moves along a long and high arc through the south and sets in the northwest - exactly as everybody observes it every summer.
Now position the figurine in the southern hemisphere, in South America, southern Africa, or Australia/New-Zealand: due to the axis tilt, the terminator lines make the daylight side much narrower. They have winter at the same time.
Move the Earth, again counterclockwise, around the sun for just one quarter of an orbit, again maintaining the same distance and having the axis point towards the same wall. That axis is now in a neutral position relative to the sun. Notice that the figurine experiences equal daylight and darkness times anywhere on Earth.
Continue to move the Earth for another quarter orbit, same distance, axis pointing towards the same wall, i.e. Polaris. The Earth is now on the other side of the sun: relative to the sun the axis is now pointing away from it. Explain why it is winter in the northern hemisphere: rotate the globe slowly and show that between sunrise and sunset the figurine is on the daylight side of the Earth for a short time. Note that for the figurine the sun appears quite low in the sky; a drawing shows that the sun rises in the southeast, moves along a short and low arc through the south and sets in the southwest - exactly as everybody observes it every winter.
In the southern hemisphere the terminator lines make the daylight side much wider. They have summer at the same time.
Thus a quarter orbit ago - when the axis was in a neutral position relative to the sun and conditions were the same everywhere - it was fall in the northern and spring in the southern hemisphere. Moving the Earth along, the next neutral position produces spring, respectively fall, for the two hemispheres. And another quarter of an orbit later, the Earth repeats its cycle through the seasons.
And that's the explanation for Earth's seasons - not that simple perhaps but it's the correct one.
What are some observations described in the in this article that can only be explained because Earth's axis is tilted?
I posted a mini-lecture explaining seasons to students at http://www.youtube.com/watch?v=pleipisn3q0 From there you can access other people's videos in which they deliver the same explanation.
Now it gets dark at a reasonable time in the evening and besides the sun and the moon we can again see planets, the occasional meteor, comets perhaps, stars, some star clusters, and two galaxies.
First find the Big Dipper low in the Northwest; then take the distance between the dipper's last two stars and extend it five times towards the Zenith (the point straight up) and you get to Polaris, the North Star, which is a semi-bright star at the end of the Little Dipper’s handle; it also marks our latitude on the Peninsula at 60 degrees above the Northern horizon. Next find the constellation Cassiopeia, in the shape of a W, on the other side of the Little Dipper, high in the Northeast. High in the sky as well, almost in the Zenith, is Cygnus, the swan; it also looks like a cross. Its brightest star Deneb connects with two other bright stars, Vega and Altair in the constellations Lyra, the harp, and Aquila, the eagle. Together they make up the prominent summer triangle. Just left of them is the Great Square of Pegasus, high in the Southeast. And to its left is the first object you are able to see anyway: ultra bright Jupiter. Turning to the West we can see bright red Arcturus setting, a sign that summer is over. And rising in the Northeast is bright yellow Capella, a corner of Auriga's pentagon. Throughout the night, all constellations move from East to West (of course, it's Earth rotating that gives us this illusion) and thus the evening Western constellations set while in the East Taurus, Orion, Gemini, and Cancer are rising throughout the night, telling us that winter is coming up.
Mercury is visible on the eastern horizon before dawn, around 5 am early this month, with best viewing between the 1st and the 10th. It's bright enough to be seen with the unaided eye but because of low contrast due to its proximity to the horizon and against a brightening morning sky it's better to scan the eastern horizon with binoculars. Around the 8th it's joined by Leo's Regulus, the two of them making a close pair in a binocular field. It would be joined by the moon later this month, but at that time Mercury will have quickly moved towards superior conjunction, i.e. to the other side of the sun, and thus out of view.
Venus just passed through superior conjunction, and thus can't be viewed this month. Starting in late October it will shine brightly in the evening all winter long.
Mars rises around 1 am in the northeast. If you happen to be up that late during the night, then you can see that this month is ideal for viewing a planet's motion: the red planet moves right-to-left (west-to-east, the true direction of motion in the solar system) through Gemini, ever getting closer to forming a straight line with Gemini's bright stars Castor and Pollux; Mars approaches from the right, forming a very acute triangle with these two stars, making a straight line around the 15th, and then moving on towards the left of these two stars.
The third quarter, almost crescent moon passes Mars from the 22nd to the 23rd. Mars moves into the pretty Beehive cluster on the 30th; you may see this star cluster with the unaided eye but with bright Mars right next to it, binoculars allow for better contrast.
Jupiter appears low on the eastern horizon after dusk. But it's of course so bright that you will notice it somewhere between the east and the west (relatively high above the southern horizon) each clear night all fall and winter long. The giant planet is joined by the gibbous moon on the 16th.
Although Saturn appears at quite some distance from the sun, the two are setting at just about the same time, making Saturn unobservable. It can be viewed prior to dawn starting in early November.
This is a good month to observe Uranus in Pisces and Neptune in Aquarius, both above the southern horizon in the evening. But they appear faint enough that finder charts and binoculars are needed. For detailed finder charts go to nakedeyeplanets.com and click on either planet's name (this seems to be a really good web site) or google "find uranus neptune chart 2011". The almost full moon joins Neptune on the 9th and Uranus on the 12th.
A word about what I called "the true direction of motion in the solar system" being west-to-east: almost all bodies in the solar system orbit counterclockwise (notable exceptions are Neptune's moon Triton and a number of small moons of the giant planets) and almost all bodies rotate counterclockwise as well (a notable exception is Venus). Since we don't notice our own Earth's counterclockwise rotation and for all practical purposes consider ourselves fixed in space, we get the illusion that everything else seems to move clockwise, which we can easily see as the sun, moon and stars seem to move east-to-west each day and night. A perfect analogy is to picture yourself sitting on a rotating merry-go-round: you get the illusion that the landscape around you rotates in the opposite direction.
But the true direction of motion, foremost of the moon and planets, can be glanced by observing from one night to the next or from one week to the next, as suggested above for Mars moving past Castor and Pollux.
Days are getting longer and nights are getting shorter, thus this will be my last column before fall. The winter constellations Orion, Gemini, Taurus, Canis Major, Auriga with all their bright stars are now visible in the west, setting during the late evening. Leo with its bright star Regulus is speeding across the sky; as I had written last month: "As a result I perceive Leo as the harbinger of spring: when it appears in the east, winter's end will soon be here and when it reaches the western horizon, flowers are in full bloom and deciduous will have regained their leaves." In addition the summer triangle comprised of the bright stars Vega, Deneb and Altair reappears in the Northeast.
As shown on the chart, the only planet out at night is Saturn, just ahead of the virtually equally bright star Spica, both low in the Southeast. The moon's progression in its orbit can be nicely observed: on the 15th the full moon appears to the right of Saturn and Spica, on the 16th between them, and on the 17th to the left.
The other planets are too close to the sun this month, because they are either close to upper conjunction (on the other side of the sun) such as Mars, Jupiter, Uranus, and Neptune or too close to the Alaskan horizon when the sun rises or sets, such as Mercury and Venus.
And if Alaska wasn't so far north, we could see four bright planets - Mercury, Venus, Mars, and Jupiter - rising together in the morning during the second week of May. But the sun's and the planets' orbits are so close to the horizon as seen from Alaska that they practically rise with the sun and that makes this planetary dance unobservable.
The Lyrid meteor shower is observable during the night of April 21/22 with an hourly rate of 10-20 meteors (small pieces of rock in interplanetary space, entering the Earth's atmosphere where - due to their large speeds and thus kinetic energy and due to friction - they disintegrate, i.e. burn up brightly). The constellation of Lyra appears high in the South after midnight and the meteors seem to emanate from that direction.
Jason Daniels, who is a fourth grade teacher at K-Beach El, forwarded the following to me from his class: “Sometimes the moon appears high above the horizon in the mornings, and other months it is not even out in the mornings.”
The moon’s orbit is a simple ellipse, thus as far as the moon’s motion is concerned, it moves along quite nicely on this ellipse. However, aside from its orbit being inclined by about 5 degrees relative to Earth’s orbit, the major culprits for making the moon hard to observe at times are the tilt of the Earth's axis and Alaska being so far north (compare this to the difficulty of observing the planetary conjunction described above). For example, during fall when the sun is still quite high in the sky, the first quarter moon is a few Zodiac constellations ahead (namely Sagittarius and Scorpius) which at night fall graze the horizon, making the moon unobservable. In spring, when the sun is again quite high in the sky, the last quarter moon is a few Zodiac constellations behind (again Sagittarius and Scorpius) which now during morning graze the horizon, making the moon again unobservable.
Another question from Jason's class: "Is the moon the only thing that affects the tides? Or is it just the main thing?"
The moon is the main body that produces tides on Earth, being responsible for 2/3 of a tide. The sun produces 1/3 of a tide. During new moon and full moon, when sun, Earth, and moon are aligned and both bodies pull in the same direction, those fractions add and we get extra large tidal ranges (good clamming during the extra low tide). During first and last quarter moon, when sun, Earth, and moon are at right angles and both bodies pull in different directions, those fractions subtract and we get extra small tidal ranges.
The constellation that always catches my eye in March is Leo, its shape quite closely resembling that of a male lion lying leisurely, watching the savannah, looking west, in the direction that it will move towards during the next couple of months. Its right front paw is the bright star Regulus.
While Leo should move across the sky as gingerly as any constellation week after week, it seems to be much speedier than. What aids or produces that perception is that sunset occurs later and later, about 20 minutes each week. Thus, with it getting darker later every evening, it seems that Leo keeps progressing across the sky faster (because we look at it later when it already has moved further west).
As a result I perceive Leo as the harbinger of spring: when it appears in the east, winter's end will soon be here and when it reaches the western horizon, flowers are in full bloom and deciduous will have regained their leaves.
Regulus follows the bright stars of winter, perhaps chasing them off: lately it's been Sirius that you've been seeing low in the south (its even brighter counterpart in the southwest is Jupiter), ahead of it are Betelgeuse, Rigel, Pollux, Castor, Capella, Aldebaran and Procyon, all of them appearing above the southern horizon.
Bright stars in the remaining sky are Deneb and Vega in the north and Arcturus rising in the east in early evening, shortly before Saturn.
Jupiter has been appearing all winter long above the southern horizon. It currently hangs very low in the southwest and west during the early evening and is joined by the waxing crescent moon on March 6.
The best show this month is put on by Mercury. Starting around March 10 look for a relatively bright object beneath Jupiter above the western horizon. During the following week the two get closer until on March 15 they're right next to each other. After that date Mercury is the one appearing higher than Jupiter. In a telescope that enlarges Mercury's size sufficiently, you can see how the speedy planet changes its phase from gibbous to crescent within just two weeks.
Saturn rises in the early evening in the southwest and is visible all night. Following right behind is Virgo's Spica. They are joined by the full moon on March 19 and 20.
Venus stays very bright but it gets lower towards the eastern horizon during dawn. The waning crescent moon is nearby on February 28 and on March 30. Neptune is close to Venus but it may be hard to spot it, and if so, only with binoculars and a good finder chart.
Uranus and Mars are in upper conjunction with the sun, i.e. they are on the other side and thus lost in the sun's glare. Pluto is very close to the southern horizon, it could be spotted and one would need an unobstructed horizon, e.g. across the ocean, a large telescope, i.e. large in aperture or diameter, so that it gathers enough light, and also a finder chart.
The winter sky is slowly rotating from the eastern towards the western horizon. Of course, it’s Earth on its orbit around Sol that makes it appear as if the sky is shifting: while we know that Earth is orbiting Sol, it really looks as if it’s the other way around because from our viewpoint we consider ourselves as standing still and everything else is moving. The former is much harder to show than the latter which is why the Earth centered Solar System had persisted for millennia. That Earth orbits Sol and rotates on its axis hinges on several crucial observations: during the 17th and 18th century Kepler discovered his laws of planetary motion which describe the solar system in a much easier way when it’s centered on Sol, then Newton developed his law of gravitation, then the masses of the planets and of Sol were determined and it made only sense that the planets should orbit Sol; due to Earth rotating, a Coriolis force is present and thus rotating low and high pressure systems exist, as well as currents circling the Seven Seas and a Foucault pendulum (see the one hanging in the UAA library) that actually swings in the same direction but Earth rotates underneath it; due to our orbit we’re covering a diameter of our almost circular ellipse of 187 million miles, making the nearest stars appear as if they shift forth and back, i.e. revealing their annual apparent parallax motion. While the behavior of many ocean currents have been known since the 1500s when Portuguese, Spanish, and English seafarers crossed the oceans, the other observations were only made in the 19th century, leading people to continue to believe in the Earth centered Solar System until long after the Copernican revolution. In fact, the only way that most of us know that Earth orbits Sol is that we are told so by teachers and read about it in books; hence my little abstract above.
The chart shows the sky close to midnight in early February and around 10 pm late in the month. The great winter stars, Sirius, Rigel, Betelgeuse, Procyon, Castor, Pollux, Capella, and Aldebaran are now sitting above the southwestern horizon. The summer stars Vega and Deneb are visible in the north, at least in Alaska. The Big Dipper is almost overhead, its handle curving towards Arcturus. In the east Saturn is rising next to Spica, both visited by Luna in its waning gibbous phase on the 20th. And – watch out – Regulus in Leo appears in the southern sky: it is a messenger that spring is around the corner. Indeed, Leo will zip across the sky in the next couple of months, assisted by the evenings getting shorter.
Jupiter may not appear on my chart but it is present, showing brightly in the west until about 9 pm. Next to it is Uranus but binoculars and a finder chart are needed (google one). Luna in its waxing crescent phase joins them on the 6th. Very vivid Venus appears in the south during dawn, joined by the waning crescent Luna on the 28th. That the two brightest planets, one bright due to its size, the other because of its proximity, are joined by a crescent Luna during dusk and dawn is an indication for them soon being lost in Sol’s glare.
Mercury, Mars, and Neptune appear too close to Sol to be observable this month.
The chart shows the sky in the later evening in early January and earlier in the evening in late January.
As long as it is clear, the sky can't get any better with the brightest stars situated high in the south. There are blue Rigel and red Betelgeuse in Orion, Sirius in Canis Major beneath it, Procyon in Canis Minor to its left, Pollux and Castor in Gemini higher up, Capella almost in the zenith, and Aldebaran and the Pleiades in Taurus, shining brightly in all their magnificence.
On the northern horizon we can see the Big Dipper, part of Ursa Major, then, closer to the zenith, are Cassiopeia, Perseus, and Andromeda. In the west Pegasus, Cygnus with Deneb, and Lyra with Vega appear on the horizon.
Leo’s Regulus rises in the evening, trailing Gemini and Cancer low in the east.
Jupiter remains the brightest night object (except for the moon of course) in the entire sky in the early evening hours; look for it above the southwestern horizon. Uranus is very close to Jupiter. Through good binoculars they appear also very close and through really string binoculars or a small telescope, Jupiter’s four largest moons can be resolved and Uranus is still in the same field. Both are joined by the waxing first quarter moon on January 9th.
Although Neptune is relatively near Jupiter as well, it is too close to the horizon too early during dusk to realistically have a chance to find and observe it.
Saturn rises shortly after midnight just south of east. It is accompanied by Virgo’s Spica and both are joined by the waning third quarter on the 24th and the 25th.
Venus rises around 5 am and then shines very brightly in the southeast and south throughout dawn. Find it next to the waning crescent moon on the 29th and 30th.
Mercury, Pluto, and Mars are rising virtually at the same time as the sun does and are therefore not observable.
Earth was just closest at 91.4 million miles to the sun on January 3rd while we will be farthest at 94.5 million miles on July 4th.
There was a partial solar eclipse on January 4th but it was only visible from Europe, Northern Africa, and parts of Asia.
You may have noticed that while the planets Mercury, Venus, Earth, Mars and so on start with a capital letter, sun and moon do not. In English only few nouns are capitalized, contrary to my native German where all nouns are (making it for example much easier for a language learner to see where a noun and thus the subject or object appear). One of the rules in English is to capitalize the proper names of specific locations such as Chesapeake Bay, Richmond, New York City, New York State, Canada, Asia, Earth, Moon, Sun. Of course that means that non-specified locations are not capitalized, such as bay, city, state, earth, moon, sun.
Hold on … how can earth, moon and sun be listed in both categories? Well, of course when any old moon, e.g. a moon of Jupiter or Saturn is referred to. But according to the Associated Press Stylebook that is not all: the very specific location of our own moon is not capitalized, in other words, on what perhaps can be considered the most important date in the history of human achievement, July 20, 1969, Neil Armstrong and Buzz Aldrin did not make a giant leap nor even take a small step onto Moon but merely strolled around on the moon. And what about the sun? While every star in its own right from an astronomical standpoint is a sun, we unambiguously think of one and only one specific location when we look at Sun in the sky. But here is what the APS has to say: “AP capitalizes the proper names of planets, including Earth, stars, constellations, etc., but lowercases sun and moon.” (see http://blogs.airspacemag.com/moon/2009/04/02/moon-vs-moon-a-study-in-arrant-pedantry/)
By the way, I should get away with incorrectly capitalizing the words sun and moon four times in this abstract – because otherwise my arguments laid out above wouldn’t work in print.
Now, I acknowledge that there is actually a difference between specified locations and the moon and the sun: it’s the words “the” and “a”. We refer to New York State as such but talk about “a state”; and as for the Earth we capitalize it in an astronomical sense when it is not preceded by an article but talk about down to earth … oh, oh, I just noticed that the APS contradicts itself: Earth often is preceded by an article and yet it is capitalized.
In conclusion, I realize that I have to obey the rules of journalism when publishing in a newspaper but I am also very close to John Spudis’ opinion (see the link posted above): “My guess is that some classically educated nit-picker who was forced to sit through endless hours on the joys of the ablative absolute in Latin class decided that the Roman-named objects of the universe were worthy of linguistic worship, but the vulgar, barbarian Germanic names given to those other three bodies did not deserve to be capitalized.”
It must have been the end-of-semester blues or business, or that I wrote another run-of-the-mill astronomy column with similar descriptions as for the previous months. Or something else - as long as I don't have to admit that I didn't pay attention and simply forgot to include the following:
On Monday, December 20, 2010 a total lunar eclipse will be visible! It's a rare enough event that - depending on having clear skies - we should observe it: the last two total lunar eclipses seen from Alaska were in 2004 and 2007 (the earlier one was visible, the latter was cloudy if I remember correctly) and the next one will be seen in 2014.
The exact full moon occurs when Sun and Moon appear opposite each other, i.e. 180 degrees apart as seen from Earth. Usually the moon orbits a little too high or too low, thus avoiding Earth's shadow. But every six months it moves right through Earth's shadow. For any given location, on average half of these lunar eclipses happen when that location is on the night side of Earth (that's the only requirement to be able to view a lunar eclipse) and a number of those eclipses are partial or penumbral, i.e. the moon is not moving through the center of Earth's shadow. That explains why a total lunar eclipse cannot be seen from the same location every six months but only every few years.
To change gears momentarily: the Kenai National Wildlife Refuge puts on a moonlight snowshoe walk on Monday, December 20, 6:00 to 7:30 pm, pre-register at 260-2839. They chose that day because it's a full moon and it happens to be the day before the winter solstice. Therefore the Refuge's snowshoe walk scheduling and the occurrence of the eclipse are not coincidental.
Then go anywhere and get ready to view the eclipse. The penumbral contact occurs around 8:30 pm; that means that as seen from the moon, the Earth is starting to obscure part of the sun but that results in a penumbral eclipse that may not show enough contrast to be actually observable for most people (yet, try to look for a faint shadow crouching in on the moon's lower left). The umbral contact occurs around 9:30 pm; now the moon's lower left doesn't get any sunlight and the partial eclipse begins (the contrast across this terminator is large enough that most people should see it, you could make a bet who is going to see it first). Around 10:40 pm totality begins; technically the entire full moon should be darkened but Earth's atmosphere is refracting sunlight towards the moon and that gives it a reddish hue. Totality lasts until around 11:50; then the moon starts to leave the umbral shadow. Around 1:00 am it's fully again in the penumbra. And around 2:00 am the eclipse is over. For the next six months the moon will then go through five full months, moving beneath Earth's shadow and thus avoiding it; on the sixth path a total lunar eclipse (or at least parts thereof) is visible on June 15, 2011, from almost anywhere in the world except North America.
You don't need anything to observe the eclipse, no telescope or binoculars. All you need to do is go outside and find the moon which should be easy, look towards the southeast. You wouldn't even have to go outside if you have a window facing southeast. You can also observe it from anywhere because the moon is so bright that light pollution around town should not affect the eclipse (unless of course you stare into a street light). I don't yet where I'll be that evening, maybe in town, maybe on Bridge Access, maybe at home, cutting a window into the southeast corner of my house.
While binoculars of course magnify the eclipsed moon, they make it appear brighter as well and with that some contrast across the terminator (the line between umbral and penumbral eclipse) may be lost. But you may figure that out for yourself.
By the way, the most comprehensive information on any eclipse is posted at http://eclipse.gsfc.nasa.gov/eclipse.html.
The chart shows the evening sky during December.
Rising in the East and gaining altitude throughout the next two months are the great winter constellations Orion with seven bright stars, among them red Betelgeuse and blue Rigel, and the stellar nursery Orion nebula; Taurus with red Aldebaran and the Pleiades; Auriga with yellow Capella; Gemini with the twin stars Castor and Pollux; the head of Canis Major with the brightest star (aside from the sun) that we can see from Earth, Sirius; Procyon in tiny Canis Minor; and very late in the evening Regulus in Leo.
Because this region of the sky hosts seven of the twenty brightest stars as seen from Earth and because there it contains quite a few easily recognizable constellations, it is my favorite region of the sky.
High in the South is the Great Square of Pegasus in the shape of a diamond; above it, close to the zenith, is Cassiopeia. Getting close to the western horizon – but never completely setting in Alaska – are the three stars that make up the summer triangle, Deneb in Cygnus, Vega in Lyra, and Altair in Aquila (that one actually sets).
In the North are Ursa Major’s Big Dipper and Ursa Minor’s Little Dipper, the latter always really close to 60 degrees, our latitude on the Kenai.
Still the brightest object during the night (as long as the moon isn’t out) is Jupiter which can be seen nicely in the south. Uranus is just to its left. The first quarter half moon joins these planets on December 12. Towards the end of the month Jupiter, the speedier of the two, is closing in on Uranus; in good binoculars the star 20 Piscium and Uranus add to the four large moons of Jupiter. Look for a greenish-blue hue for Uranus.
Neptune could be glimpsed in the early evening low in the southwest. Google “Neptune finder chart” because that is needed. On December 10 the almost half moon could be used as a first guide.
Saturn, which rises around 1 am, is best seen in the pre-dawn hours very low on the southern horizon. The third quarter half moon is near Saturn on December 28.
But more prominent is Venus sitting on the southeastern horizon. If you connect the two you can see where the sun will rise around 9 am. The waning crescent moon appears near Venus on December 31.
I have to admit that late this fall Jupiter and Venus fooled me at times as I would see the giant in the evening and Earth’s cloudy and toxic twin in the morning in the same spot.
Mercury and Mars currently appear too close to the sun to be viewed.
In October I published the first half of a quiz (questions 1 through 6) addressing common misconceptions. Here is the second half:
7. The Earth rotates once every ... (a) 23h 56m 4s, (b) 23 hours, (c) 24 hours, (d) the Earth doesn’t rotate.
8. A day on Earth is ... (a) 24 hours long because it’s a combination of Earth’s 23h 56m 4s rotation and the Earth moving a little along in its orbit during one rotation which takes an extra 3m 56s until the Sun appears in the same location, (b) 23h 56m 4s long, (c) 23 hours long, (d) there is no day on Earth.
9. A location on the Earth has a high tide ... (a) when it is facing the Moon and when it is on the other side (of Earth), (b) twice a day, (c) only when it is facing the Moon.
10. A spring tide occurs … (a) every two weeks, during new moon when the moon appears between sun and Earth, and during full moon when sun and moon are opposite each other; both moon and sun are tugging together in the same locations on the Earth’s surface, producing extra high tides, (b) during spring, (c) between new and full moon.
11. During totality during a total solar eclipse ... (a) one may look at the Sun but should exhibit caution, (b) the behavior of animals and plants is affected by the onset of darkness, (c) the Moon is exactly in line between Earth and Sun, casting its shadow onto Earth; this happens once every six months, (d) one must not look at the Sun.
12. Our Moon ... (a) is visible for the same amount of time during the day as it is during the night – but (i) both Sun and atmosphere outshine it and (ii) its phases are rather crescent when seen during the day while they’re more gibbous during the night, (b) is never visible during the day.
Some of the popular – but incorrect – answers are 7.c, 9.c, 11.d, 12.b.
The correct answers are 7.a, 8.a, 9.ab, 10.a, 11.abc, 12.a.
The diagram shows the sky in November at around 11 pm. Compared to October the sky shifted somewhat towards the east with Hercules on the northern horizon. Prominent constellations and stars are the Big Dipper (part of Ursa Major) high in the northeast and the Little Dipper high in the north, Cygnus with Deneb, Lyra with Vega and Aquila with Altair now low in the northwest. These three stars form the summer triangle: it's perhaps comforting that in Alaska we can see this summer triangle all winter along, albeit on the horizon. Cassiopeia appears overhead, in the zenith, Pegasus' square/diamond right above the very bright Jupiter in the southwest. In the east Gemini with Castor and Pollux, Cancer with the Beehive cluster and Leo have risen, following Orion with red Betelgeuse and blue Rigel which are now quite high in the south. Auriga with Capella and Taurus with Aldebaran and the Pleiades star cluster appear now high in the southeast.
Aside from Jupiter which can be seen all evening, Uranus is still accompanying it. Neptune can be seen low in the southwest early in the evening. The latter two can be found with strong and stable binoculars and after googling "Uranus Neptune 2010 -astrology" for good sky charts (the minus hopefully eliminates misleading astrology web sites). Between November 12th and 16th we can see how the waxing half moon turns into a gibbous moon as it moves closer and passes Neptune, Uranus and Jupiter.
Saturn rises in the southeast during predawn. The very crescent moon joins it on November 3.
Later this month Venus takes over in the spot in the southeast at the same time during predawn with Saturn nearby. Between November 28th and December 2nd we can see how the waning half moon turns into a crescent as it moves closer and passes Saturn and Venus; on December 1 these three should make for a pretty triangle.
Mercury and Mars set and rise together with the sun in Alaska and thus cannot be seen.
The following are some great sights this - and every - winter. There is too much detail involved for finding them, so that I need to refer to better skycharts than the one I can reproduce here. I suggest google.com/sky: search for each object, zoom out quite a bit, turn on constellations, then compare to my chart (you need mine as a starting point because google sky cannot be adjusted to any given location), then turn off constellations because that makes it easier to identify them. Also, watch my recording at tinyurl.com/kpc-astronomy in which I visit all of these.
1. The Milky Way, our own galaxy, harboring more than 100 billion stars: it spans from one horizon across Cygnus, Cepheus, Cassiopeia, Auriga, Gemini to the opposite horizon.
2. The Hercules Cluster, a globular cluster of about 100,000 stars: this is the only one for which you need binoculars; find it 2/3 of the way between the stars zeta and eta Herculi.
3. Mizar and Alcor in Ursa Major, a double star: this is the star in the bend of the Big Dipper's handle; look closely and you see that it is actually two stars.
4. The Beehive in Cancer, an open cluster of about 1000 stars: somewhat fainter than the Pleiades but very pretty, almost half way between Castor & Pollux and Regulus.
5. The Orion Nebula, a birth place for stars: it forms the sword of Orion, right beneath its belt of three stars.
6. The Pleiades in Taurus, an open cluster of about 1000 stars: of these you can easily see the six or seven brightest.
7. The Andromeda Galaxy, our closest galactic neighbor at only 2 million lightyears away: look at it with averted vision and you'll see a small elongated smudge.
8. The Double Cluster in Perseus, two open clusters: they can be seen about one third of the way from Auriga to Cassiopeia, again use averted vision.
9. Algol in Perseus, an eclipsing binary that fades appreciably every 3 days: it forms a nice right triangle with two (usually) barely brighter stars in Perseus in Andromeda.
The diagram shows the very late evening sky in early October - that way I am able to squeeze in the first stars of winter. Sorry about that.
Compared to September the sky shifted somewhat towards the east with Bootes setting in the northeast; its brightest star Arcturus can be seen in the early evening on the northeastern horizon. Prominent constellations and stars are the Big Dipper low and the Little Dipper high in the north, Cygnus with Deneb, Lyra with Vega and Aquila with Altair still high in the west. These three stars form the summer triangle: it's perhaps comforting that in Alaska we can see this summer triangle all winter along, albeit on the horizon. Cassiopeia appears overhead, in the zenith, Pegasus' square/diamond right above the very bright Jupiter in the south. In the east Orion rises with Betelgeuse and Rigel, following Taurus with Aldebaran and the Pleiades star cluster.
Aside from Jupiter which can be seen all evening, Uranus appears close to the biggest planet, while Neptune can be seen for most of the evening; the latter two can be found with strong and stable binoculars and after googling "Uranus Neptune 2010 -astrology" for good sky charts (the minus hopefully eliminates misleading astrology web sites).
The other planets, Mercury, Saturn, Venus, and Mars all set and rise together with the sun in Alaska and thus cannot be seen.
I thought I would try something different this month and thus present a surprise quiz that I hand early on to astronomy students. It is based on trying to eradicate common misconceptions. Here is the the first half (the second half will follow in a future column):
1. Seasons: it is warm in summer because ... (a) the Earth’s axis is tilted at a 23 degree angle and thus in summer we get more direct sunlight and the days are longer, (b) winter follows fall, (c) Earth is closer to the sun in summer than in winter, (d) of a multitude of reasons that are too long-winded to explain on less than 43 pages.
2. Our moon exhibits phases because ... (a) as it orbits Earth more respectively less of its lit up half (lit up by our sun) is visible from Earth depending on its position in its orbit, (b) only half of it shines and as it turns it acts like a beacon, (c) because throughout the month Earth’s shadow covers more or less of our moon, (d) it doesn’t rotate and thus reflects Earth’s light differently.
3. Gravitation means that ... (a) our sun attracts the planets and each planet attracts its moon(s), (b) all objects with any amount of mass attract each other; this includes all planets, sun, moons attracting each other, (c) an object in motion stays in motion.
4. The gravitational force with which the Earth attracts the author is 195 lb. The gravitational force with which the author attracts the Earth is ... (a) greater than that, (b) 195 lb, (c) much less than that.
5. The Earth’s orbit is ... (a) almost circular, (b) perfectly circular, (c) very elliptical; (d) the Earth doesn’t orbit - the sun does.
6. The Earth is ... (a) closest to the sun in early January (but barely) and farthest in early July; (the sun is very close to the center of the Earth’s nearly circular orbit), (b) big, (c) closest to the sun in summer and farthest in winter, (d) small.
Some of the popular – but totally incorrect – answers are 1.c, 2.c, 4.c, 5.c, 6.c.
The main reason that some of these incorrect answers are so prevalent is that on first sight they seem to make sense, e.g. on seasons, moon’s phases, gravitation (that’s why I listed them first).
The correct answers are 1.a, 2.a, 3.b (a is not wrong but it’s incomplete), 4.b, 5.a, 6.a.
After a rainy summer we could try for a warmer fall with clear skies as it gets darker earlier in the evening. The following describes the starry evening sky throughout September.
First find the Big Dipper low in the Northwest; then take the distance between the dipper's last two stars and extend it five times towards the Zenith (the point straight up) and you get to Polaris, the North Star, which is a semi-bright star at the end of the Little Dipper’s handle; it also marks our latitude on the Peninsula at 60 degrees above the Northern horizon. Next find the constellation Cassiopeia, in the shape of a W, on the other side of the Little Dipper, high in the Northeast. High in the sky as well, almost in the Zenith, is Cygnus, the swan; it also looks like a cross. Its brightest star Deneb connects with two other bright stars, Vega and Altair in the constellations Lyra, the harp, and Aquila, the eagle. Together they make up the prominent summer triangle. Just left of them is the Great Square of Pegasus, high in the Southeast. And beneath it is the first object you are able to see anyway, ultra bright Jupiter. Turning to the West we can see bright red Arcturus setting, a sign that summer is over. And rising in the Northeast is bright yellow Capella, a corner of Auriga's pentagon. Throughout the night, all constellations move from East to West (of course, it's Earth rotating that gives us this illusion) and thus the evening Western constellations set while in the East Taurus, Orion, Gemini, and Cancer are rising throughout the night, telling us that winter is coming up.
According to information published in Sky & Telescope and Astronomy magazines and on the internet, all planets should be visible this month. However, that is not the case for Alaska: Mercury, Saturn, the bright star Spica, Mars and Venus are all strung along a line that - as seen from more Southern latitudes - would be angled above the Eastern horizon after sunset; in Alaska that line of star and three planets is parallel to the horizon and therefore they all - unfortunately - slip beneath the Eastern horizon during sunset.
That leaves a very bright Jupiter as the sole hold out among the bright planets, situated low in the Southeast: it is easily the first object that pops into view after sunset. Aside from its moons which can be seen with strong and stable binoculars (I recommend propping your elbows on a car's roof), it also currently guides you to Uranus which appears right above it.
Neptune can be found to the lower right of these two, very low in South. Both of these outer gaseous planets can be found with those strong and stable binoculars and good sky charts, posted e.g. at http://media.skyandtelescope.com/documents/Uranus_Neptune_2010.pdf (this is copyrighted, so I cannot reproduce them here). By the way, Neptune is so far out (about 3 billion miles) that it would take a truck driver averaging 150,000 miles per year about 20,000 years to get there. Neptune on the other hand, orbiting the Sun at 12,000 mph without ever taking a break, makes its journey in just 165 years. And since it was discovered in 1846 (due to a joint English/French/German effort), it will mark its first complete orbit since its discovery in July of next year.
In contrast Mercury needs a mere three months to orbit the Sun at 100,000 mph: while the speediest planet is in line with the Sun on September 3 (this is called inferior conjunction), just two weeks later, Mercury reaches its greatest elongation and is nicely situated low in the East before the Sun rises, between about September 15 and 25.
The almost full Moon joins Neptune on the 19th, making it easier to find the planet. The full Moon can be found right above Uranus and Jupiter on the 22nd.
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Days are getting longer and nights are getting shorter. We're also leaving the freezing cold behind. As we all love winter's benefits, I - and perhaps many of us - surely regret that our beloved starry skies will take a back seat soon. Therefore, after this article, see you again in August or September.
But at least we get some nice views for a good-bye. With Daylight Savings Time having started, it doesn't get dark until 10 pm or even later and therefore the diagram shows the Southwestern sky between 10 pm and 12 am throughout April. This late in the season, many of the brilliant stars of winter are either gone or hard to detect. Therefore look early in the month in the West for Sirius and Orion with Betelgeuse and Rigel, Aldebaran and the Pleiades. Still visible all month are the twins Castor and Pollux, reddish Mars near Cancer's Beehive and between Regulus and the twin stars, then Procyon, Capella in its pentagon of Auriga and, having shifted from East to West throughout late winter is Saturn between Leo's Regulus and Spica. Saturn is actually of virtually the same brightness as these bright stars and thus blends in pretty good, so you would need this diagram or a starfinder to locate Saturn; both Mars and Saturn are also exaggerated in this diagram: you'd need a telescope to see their disks and Saturn's rings.
Mercury is quite possible this month. The best day would be Thursday, April 15, around 9:30 pm during dusk. It would be easiest to find because it has a couple of helpers. Yet it may still be tricky because it's very low on the Western horizon: look for bright Venus and the crescent Moon just right of Venus, then follow the crescent's light pointing towards the horizon and you you notice Mercury.
Venus can be seen all month during dusk and during the summer it may be the only (aside from Sun and Moon) celestial object visible - due to its great brightness - during the short and barely dark nights. You would find it near the Northwestern horizon (because that's where the Sun sets in the summer) around midnight.
Finding Mars and Saturn is explained above and shown in the diagram. Mars is joined by the waxing half Moon right beneath it on April 21, Saturn by the waxing gibbous Moon on April 24 and then the 25th, to the lower right and then lower left.
Jupiter, Uranus, Neptune and Pluto are not visible since they rise at the same time as the Sun does.
The starry sky is now at its best with the most prominent stars being well placed high in the South: blue Rigel and red Betelgeuse in Orion, Sirius beneath it, Procyon to its left, Pollux and Castor higher up, Capella almost in the Zenith, and Aldebaran and the Pleiades completing the splendor.
The Big Dipper starts out close on the Northern horizon but Cassiopeia, Perseus, and Andromeda are close to the Zenith. In the West Cygnus and Pegasus are about to set while bright Vega, being circumpolar in Alaska, stays close to the horizon.
Leo’s Regulus and Mars rise in the evening, trailing Gemini and Cancer low in the East.
The chart shows the sky around 10 pm in early January and 8 pm in late January. I inserted grid lines showing the altitude at 30, 60, and 90 degrees, and the azimuth also in increments of 30 degrees, starting from North. I chose not to show all constellations – e.g. faint constellations Eridanus, Cetus, Pisces, Aquarius in the Southwest are missing – because the chart is already crowded enough.
Jupiter remains the brightest night object (save our Moon of course) in the entire sky in the early evening hours; look for it above the Southwestern horizon.
Neptune is near Jupiter, Uranus to the upper left just below the circlet of Pisces which itself is south of Pegasus’ Great Square.
All three planets are joined by the waxing crescent Moon from the 17th through the 19th.
Mars is visible all night, rising just ahead of Regulus in the evening in the Northeast. The full Moon is near Mars on the 29th.
Saturn rises around 1 am in the East, ahead of Virgo’s Spica. The waning gibbous Moon is near it on February 2nd.
Venus is in superior conjunction on the other side of the Sun, hidden by its glare.
Mercury rises just ahead of the Sun in mid to late January but it’s so low on the Southeastern horizon in Alaska that it’s close to impossible to spot – unless you happen to be in Chinitna Bay during a clear January dawn, looking in that direction.
Earth is nearest the Sun on Jan 3rd (91.4 million miles) while we will be farthest on July 6 (94.5 million miles).
I accidentally forgot to write about a couple of things last semester – but I do have excuses.
There was a partial lunar eclipse during the full Moon on December 31 visible from Alaska. The reason I missed it is threefold: the eclipse map I’m using shows that predominantly Africa, Asia, and Europe saw the eclipse; the Earth’s shadow cut out only a very small portion of the Moon; and the Moon appeared very low above the Western horizon during morning dawn at around 10 am. Yet at http://www.adn.com/188/story/1074104.html we can see that Marc Lester captured an image that belies my assumptions of reasons to leave out information of this eclipse.
So as not repeat the same lapse, I refer to June 26, 2010, midnight through 4 am, during which time we can see a similar (un)favorable partial lunar eclipse from Southern Alaska. And this one I definitely won’t forget to mention in detail: a great total lunar eclipse on December 21, 2010, visible from all of North America.
There was a “blue moon” on December 31. The reason I missed it is onefold: astronomically it’s not important (only for calendar aficionados it’s interesting).
But in response I read up on it and found out that our current interpretation of what a blue moon is, is founded on a misinterpretation perpetuated by the venerable astronomy sources Sky & Telescope magazine (see the article “What’s a Blue Moon” on skypub.com) and the popular StarDate radio show. To call the second moon in a month a blue moon rests on an S&T error made in 1945 and spread to a wide audience by StarDate in 1980.
Instead the presumably original definition for a blue moon is based on the given names for each full moon throughout the year as listed in the Farmer’s Almanac. Each season usually hosts three full moons, e.g. winter the Full Wolf, Snow, and Worm Moon, with names adopted and adapted by European settlers from Algonquin tribes.
However, the Moon’s phases take a 29.5 day long cycle, so about every third year will see a season with four full moons instead of three. The third of those four full moons within one season was called a Blue Moon. That definition presumably goes back to a computus used 500 years ago in England for calculating the date for Easter which could be messed up if there are four full moons in winter. To keep the last full moon of the season as the correct one, the third one was renamed “belewe”, an old English word meaning either ‘blue’ or ‘betrayer’, hence the name origin. Now the first, second, betrayer, third, would keep the Easter calculation (first Sunday after first full Moon after spring equinox) intact.
According to that original definition autumn of 2010 will see four full Moons with the Full Corn in September, the Full Harvest in October, the Full Blue on November 21, and the Full Beaver Moon in December.
The chart shows the evening sky during December – 8 pm early and 6 pm late in the month. Stars with an asterisk * attached are marked as dots on the chart.
Still high in the sky, now in the West, is the “summer” triangle, made up of Lyra’s Vega*, Cygnus’ Deneb* - a long necked swan, shown as the northern cross on the chart - and Aquila’s Altair*. From South to North we see several prominent constellations: the great square of Pegasus, also appearing as a baseball diamond with Markab at home base and Scheat, Alpheratz and Algenib on first, second and third base, the W of Cassiopeia with its brighter stars Schedar and Caph, the fainter house of Cepheus, the little and big dippers of Ursa Minor and Major – the small and large bears – and the bear watcher Bootes which is setting in the North. Ursa Minor’s brighter stars are Polaris at the end of the Little Dipper’s handle and Kochab and Pherkad at the end of dipper; to see the remaining four stars in between your eyes need to adjust to the darkness first before they become visible. Ursa Major’s prominent stars are Merak and Dubhe in its dipper which are also the pointer stars for Polaris.
Orion, the Hunter, is about to rise. It is many people’s favorite because of its brilliance. Four stars arranged in a rectangle - red Betelgeuse*, blue Rigel*, Bellatrix, and Saiph - outline the body, while three stars make up the belt - Alnitak, Alinalam, Mintaka - with the Orion nebula as the sword beneath it. Above Orion you find Taurus, part of it in the shape of an arrowhead including red Aldebaran*. And above that are the Pleiades* or Seven Sisters, a must for binoculars. To Taurus’ left is the pentagon Auriga with yellow Capella*. Beneath Capella appear Castor* and Pollux*, the twins in Gemini. And then we close this circle towards the horizon, with Procyon and the Number One: Sirius, the brightest star in the entire sky; both of which will rise about two to three hours after Orion.
Jupiter remains the brightest night object (save our Moon of course) in the entire sky these days. Neptune and
Uranus can be spotted in Capricornus and Aquarius just above the Southern horizon, with the best views during early evenings; on how to find the latter two, check out skypub.com (specifically http://media.skyandtelescope.com/documents/Uranus_Neptune09.pdf) which has some good finder
charts and also features an online interactive star map. Throughout the month, as Jupiter is moving West-East (a planet's true motion as seen against the stars), i.e. right-left, the giant planet is closing in on Neptune, reducing their distance from 3 to less than 1 degree (they will meet, i.e. be in conjunction, on December 20). The crescent Moon is also nearby Jupiter and Neptune on the 20th and 21st.
Uranus is just east (left) from these two planets, straight down from the Great Square and just below the Circlet of Pisces (which isn't shown on my rudimentary chart). The by first quarter half Moon passes above Uranus on the 23rd.
Mars rises around 11 pm in early and 9 am in late December and is visible for the rest of the night. The waning gibbous Moon passes beneath Mars on the 6th and 7th. (The orbits of the planet and of our Moon are tilted or inclined with our own orbit, which explains why our Moon is able to pass beneath one planet and above another.)
Saturn rises between 2 and 4 am. Virgo's brightest star Spica, Saturn, Regulus, and Mars produce a line of bright objects stretching across the Southeast and Southern sky before sunrise, with the stars of winter, Pollux, Castor, Procyon, Betelgeuse, etc., producing a beautiful Southwestern sky. The third quarter half Moon appears beneath Saturn on the 9th and 10th.
Venus is rising together with our Sun and is thus invisible during December. Although it will emerge from the Sun's glare in February, it may be hard to spot this winter.
Mercury sets during dusk around Dec 15 in the Southwest. But it's so close to the horizon that one would have to get to a very favorable observing spot to see it; actually the northern Kenai Beach with an unobstructed view across Cook Inlet towards the Southwest could work.
Follow the sunrise and sunset times throughout December and you can pinpoint the earliest sunset and the latest sunrise. Near the solstices in June and December, sunrise and sunset times bottom or top out. And thus no difference seems to show up for two weeks: sunset slowly changes from 16:02 on Dec 1 to 15:54 on Dec 11, bottoms out at 15:53 Dec 12-20 (if one nitpicks for seconds, Dec 16 would be the earliest sunset), then slowly changes to 16:04 on Dec 31 (my data are obtained from the US Naval Observatory web site). (In contrast, around the equinoxes in March and September sunrise and sunset times change 3 minutes every day for a total of up to 90 minutes in one month.)
The earliest sunset occurs thus on Dec 16 at 15:53, the shortest day on Dec 21 (10:11 to 15:54; 5 hours 43 minutes), the latest sunrise on Dec 26 at 10:12.
The differences are so little that of course we don't notice. But it is curious that the earliest sunset and the latest sunrise are not occurring on the day of the winter solstice. The explanation for that is based on the tilt of the Earth's axis in combination with Earth's slightly elliptical orbit (making for a faster orbital speed when we're closest to the Sun, which happens in Dec and Jan). While the Earth's rotation is very constant (23h 56m 4.1s), the length of one day-and-night is affected by the aforementioned tilt-of-axis and change-of-orbital-speed. On first sight that accounts for the remaining 3m 55.9s for an average day-and-night being 24h 0m 0s long. But that's an average. Since the Earth's tilt relative to the Sun is changing (of course towards the Sun makes summer and away from the Sun winter; not to be confused with being closest to the Sun in Jan and farthest in July which - due to only a minute difference in distance - has no influence on the seasons) and its orbital speed is changing, the length of day-and-night also changes by as much as 30 seconds. Since those seconds accumulate - albeit rather slowly - latest sunrise and earliest sunset occur on different days in December than the solstice suggests.
Event this month: visit the Challenger Learning Center in Kenai on Tuesday, December 29 for their Mini-missions. Call 283-2000.
Winter has almost arrived (snow anybody, though?) and that means that the bounty of the beautiful
winter sky charms us once more. The accompanying chart is set for 12 am in early November, for 11 pm in the middle of the month, and for late
in the month. To use (parts of) the chart during the early evening, imagine rotating everything clockwise around the P of Polaris, thus stars in the East appear closer to the horizon earlier in the evening, stars in the West appear higher in the Southern sky.
During the following description, stars with an asterisk * attached to them
are marked with a letter on the chart. The constellations of Orion, Taurus, Auriga and Gemini
are visible in the Southeast. Inside these constellations are the bright
stars of winter: red *Betelgeuse and *Aldebaran, blue *Rigel , yellow *Capella
and the twins' *Castor and *Pollux; the latter two make a fine triangle with
Mars. Also included is the star cluster of the Pleiades, best viewed with
binoculars through which up to 50 stars may be seen. Soon the bright stars Procyon
and Sirius will follow as they rise in the Southeast later in the evening.
Now near the Zenith are Cassiopeia's W, the House
of Cepheus, Pegasus’ Great Square and the swan Cygnus’ northern
Cross.
Always in the same place is the Little Dipper with *Polaris and atop the
Northern horizon appears the Big Dipper. The kite-shaped Bootes with red
Arcturus is now setting while the summer triangle consisting of *Deneb (the
Swan's tail), *Vega and *Altair is getting closer to the Western horizon.
Right now Jupiter (the brightest night object, save our Moon, in the entire sky these days), Neptune and
Uranus can be spotted in Capricornus and Aquarius just above the Southern horizon, with the best views during early evenings; on how to find the latter two, check out skypub.com (specifically http://media.skyandtelescope.com/documents/Uranus_Neptune09.pdf) which has some good finder
charts and also features an online interactive star map. Throughout the month, as Jupiter is moving West-East (a planet's true motion as seen against the stars), i.e. right-left, the giant planet is closing in on Neptune, reducing their distance from 6 to 3 degrees (they will meet, i.e. be in conjunction, on December 20). The first-quarter half Moon stands above Jupiter and Neptune on the 23rd.
Uranus is just east (left) from these two planets, straight down from the Great Square and just below the Circlet of Pisces (which isn't shown on my rudimentary chart). The by now waxing gibbous Moon passes above Uranus from the 25th to the 26th.
Mars rises around midnight throughout the month and it and the closest bright star, Regulus in Leo, stand highest in the South at around 7 am. So if you commute around that time, especially to Homer or through Turnagain Pass going South, that red planet is guiding you. From October 31 to November 2, Mars is passing through the pretty Beehive cluster in Cancer; I consider it pretty because it's second in brightness only to the Pleiades, can be seen with the unaided eye, and, well looks handsomely in binoculars. The third-quarter half Moon passes beneath Mars on the 8th and 9th. (The orbits of the planet and of our Moon are tilted or inclined with our own orbit, which explains why our Moon is able to pass beneath one planet and above another.)
Saturn rises around 5 am. Virgo's brightest star Spica, Saturn, Regulus, and Mars produce a line of bright objects stretching across the Southeast and Southern sky before sunrise, with the stars of winter, Pollux, Castor, Procyon, Betelgeuse, etc., picking up the slack in the Southwestern sky. The waning crescent Moon is below Saturn on the 12th.
Venus, although much brighter than all other planets (only Jupiter is able to match it occasionally), may be hard to see because it's rising just before our Sun in the Southeast. It is joined by a very thin crescent on the 14th.
Mercury is exactly on the other side of the Sun, "an event that's rare but completely unobservable" (Sky & Telescope, November 2009, p.48).
The Leonid meteor shower peaks between midnight and dawn of the 17th. As Earth passes through the orbit of comet Temple-Tuttle, pieces of debris from that comet, strewn throughout its orbit, are entering Earth's atmosphere where they evaporate (because the atmosphere decelerates them so much that a lot of their kinetic energy is transformed into heat, hot enough to be easily and spectacularly seen). Since the orbits of Earth and Temple-Tuttle cross in a place in our solar system where we are facing the constellation Leo, these meteors seem to emanate from that constellation and are thus called Leonids.
Visit the Challenger Learning Center in Kenai on November 20 for their Star Party, 6-8 pm. Call 283-2000.
The stars of fall are back: I highlighted easy to find
constellations such as the Big Dipper, the fainter Little Dipper, kite-shaped
Bootes, W-shaped Cassiopeia, house-like fainter Cepheus, cross-like Cygnus, the
dashed-line Summer Triangle, the Great Square of Pegasus, the arrow-like snout
of Taurus, the pentagon-shaped Auriga.
I also highlighted the brightest stars with big dots. Big on star charts
means brighter (not larger - no matter how much stars are "magnified" in a
telescope, they're still pinpoints). They won't appear bigger in a telescope but brighter and perhaps
their color shows better, indicating the surface temperature of a star, ranging
from 5000 F for "cold" red stars, 11000 F for yellow stars, 20000 F
for white ones up to 40000 F for "hot" blue stars.
Indicated on the chart - starting in the Northeast and following the horizon - are red Aldebaran in Taurus, yellow Capella in Auriga, Gemini's
white Castor and orange Pollux, red Arcturus in
Bootes (the Big Dipper's handle points to this star) and white Deneb, Vega
and Altair which make up the summer triangle; the fainter yellow North star Polaris
is designated by the little cross at the end of the Little Dipper's handle.
To the upper right of Aldebaran, look at the Pleiades or Seven
Sisters. Also of note is Albireo, actually a double star, at the lower
end of Cygnus' cross with the brighter component showing at a golden yellow in
binoculars and the fainter one being blue.
The arrows show the direction in which the stars seemingly turn around Polaris
- due to Earth rotating in the opposite direction under the stars - with stars
setting in the West and new ones rising in the East.
Aside from these prominent stars and constellations, it's worth noting fainter
and harder to see constellations. Starting from the Southern horizon
and going up towards Polaris I briefly describe Capricornus, Aquarius, Equuleus,
Delphinus, Lacerta and Cepheus. Capricornus and Aquarius are part of the
Zodiac, i.e. our Sun, our Moon and planets and most asteroids can be found
within these twelve constellations. Right now Jupiter (the brightest night object, save our Moon, in the entire sky these days), Neptune and
Uranus can be spotted in Capricornus and Aquarius; on how to find the latter two, check out skypub.com which has some good finder
charts and also features an online interactive star map. Equuleus means "little horse" and consists mainly
of four dim stars half way between Aquila and Pegasus' Great Square. Just
to the left - or better referred to as East - of Aquila's bright star Altair
lies the equally small Delphinus which obviously means
"dolphin". John Sanford in his "Observing the
Constellations" uses a very nice description: "Delphinus has one of
the most distinctive shapes, that of a slightly flattened diamond with a couple
of fainter stars as a tail." Personally it's one my favorite gems
when I casually look at the heavens without binoculars or a telescope. Lacerta, the lizard, lies to the upper right - better is northwest - of
Pegasus Great Square. Look for eight stars making a small zig-zag
line. Cepheus, the king, is a house shaped constellation between the more
prominent Cassiopeia, Cygnus and Ursa Minor. It takes a minute or so to
find the house because Cepheus consists of faint stars and lies on the edge of
our Milky Way which shows a lot of stars in that region.
A couple of faint deep sky objects worth noting are the Andromeda nebula and the double cluster in Perseus. They are faint to the naked eye but can easily be spotted with binoculars. Unfortunately my chart can't show enough detail to pinpoint them accurately, thus I refer the reader to sky charts in astronomy magazines and on the internet, e.g. google.com/sky.
I already mentioned some planets and here are the remaining ones: Venus, Mercury, and Saturn are presently emerging out of the Sun's glare but they are still hard to see in Alaska because they remain so close to the Eastern horizon during dawn. Mars rises in the East around midnight, visible until dawn, moving from Gemini into Cancer. In the middle of month it lines up with Castor and Pollux. A nice project yields the discovery of a planet's motion: observe Mars prior to October 10 and you see it distinctly to the right of (West of) Castor and Pollux; then observe it after October 15 and you see that it moved to their left (towards East) and is put some distance in between.
The planets are joined by our Moon on these dates: Mars and the waning half moon on 10/11&12; Mercury, Venus, and Saturn and the crescent moon on 10/15&16; Jupiter and the waxing half moon on 10/26.
Start looking out for the Aurora.
Now we are able to actually see stars in once again dark environs; the following description holds true for all evenings in September. To first orientate yourself find the Big Dipper low in the Northwest; then extend the dipper's last two stars high into the North to find Polaris, the North Star, and the Little Dipper; with the Big Dipper on one side of Polaris, find the constellation Cassiopeia, a nicely shaped W, on the other side of Polaris high in the Northeast. Back to the Big Dipper, follow the curve of its handle towards the bright Red Giant Arcturus low in the West with its constellation of Bootes above, appearing as a kite or cone shape. Notice the bowl shaped Corona Borealis to its upper left. Prominently high overhead and extending to the South is the Summer Triangle, made up of the three bright stars Vega, Deneb and Altair. Deneb's constellation of Cygnus, the Swan, in a cross shape is easily seen; Vega's small rectangular shaped Lyra, the Harp, is prominent as well; while Altair's Aquila or Eagle may be depicted by its wings. But just on the upper left of Altair is the dolphin shaped small constellation Delphinus. Also prominent in the Southeast are the Great Square of Pegasus and low in the Northeast bright yellowish Capella with its pentagon shaped constellation Auriga. By morning constellations have rotated towards the West with some of them having set while others have risen in the East. Those are Orion, Taurus, Gemini, Cancer and Leo as well as the planets described above.
By far the brightest object now is Jupiter which has climbed out of the (in Alaska) impossibly low constellations of Scorpius and Sagittarius and this year resides in Capricornus. You can spot it shining brilliantly above the Southern horizon during late evenings. You can also see its four large moons in good, stable binoculars and in a small telescope - except during the night of September 2/3: Io and Callisto are behind Jupiter or eclipsed by its shadow. Europa and Ganymede are in front of Jupiter casting their shadows on the giant planet; thus Jupiter appears moonless for a few hours. (A larger telescope would show Europa and Ganymede's dark shadows on Jupiter's disk.)
This
month may be the best to find Uranus and Neptune, two faint planets that can be
seen with binoculars. My chart gives you a general idea of where they are
around midnight, especially in relation to the prominent Summer Triangle
and Jupiter (picture everything further left/East in the sky if you observe earlier in the evening); you probably get Neptune in your view when you slowly slide your binoculars from Jupiter to the left/East by a few degrees. Nevertheless, best are more detailed charts for which this link may work best:
http://media.skyandtelescope.com/documents/Uranus_Neptune09.pdf (I
don’t reproduce these charts because of their copyright). Both planets
should be high enough, 25 and 15 degrees respectively above the Southern
horizon - as long as only a few trees obstruct your view.
Saturn is in superior conjunction, i.e. on the other side of
the Sun, and therefore cannot be viewed until October prior to dawn. We therefore miss viewing its rings edge-on, a phenomenon that happens every 14 to 15 years (half of Saturn's orbit) when instead of presenting its rings in all their glory, they all but vanish from our viewpoint on Earth, transforming Saturn into an ordinary planetary disk. But Saturn and its rings will be back all winter, albeit its rings will be still almost edge-on.
Mercury is also hidden in the Sun's glare. But Venus appears prior to and during dawn. Around the 19th it would make a pretty couple with Leo's brightest star Regulus but Venus by far outshines the 21st brightest star in the sky. Maybe it's a pretty coupling anyway.
Mars rises in the East around midnight, residing in Gemini.
The planets are joined by our Moon on these dates: Jupiter and Neptune and the full moon on 9/1 and 9/2; Uranus and the full moon on 9/4 (using the Moon as a guide may make it easier to locate Neptune and Uranus but its brightness will make it harder to actually view them; my recommendation: remember where they are and observe them a week later when the moon has moved on); Mars and the half moon on 9/13; Venus and a very thin crescent moon on 9/16; Sun, Mercury, and Saturn and the new moon on 9/18, which is of course invisible; and again Jupiter and Neptune and the almost full moon on 9/28 and 9/29.
Have fun observing: I'm looking forward to hopefully clear
skies this winter.
Days are getting longer and nights are getting
shorter. We're also leaving the freezing cold behind. As we all love
winter's benefits, we surely regret that our beloved starry skies will take a
back seat soon. Therefore, after this article, see you again in August or September.
But at least we get some nice views for a good-bye. With
Daylight Savings Time having started, it doesn't get dark until 10 pm or even
later and therefore the diagram shows the Western sky around 11 pm towards the
end of April. This late in the season, many of the brilliant stars of winter
are either gone or hard to detect. Therefore look early in the month in the
West for Sirius and Orion with Betelgeuse and Rigel, Aldebaran and the
Pleiades. Still visible all month are the twins Castor and Pollux in the middle
of the diagram, Procyon below and left of middle, Capella in its pentagon of
Auriga on the right and, having shifted from East to West throughout late
winter are Leo with Regulus and Saturn nearby. The latter is actually of
virtually the same brightness as these bright stars and thus blends in pretty
good, so you would need this diagram or a starfinder to locate Saturn.
All five naked eye planets are visible in April, for the first time in quite some time.
Mercury can be spotted very low on the NW horizon after sunset, from about 10:30 pm until almost midnight, between mid-April and the end of April. Mercury is the brightest object in this part of the sky, although Betelgeuse and Aldebaran are almost as bright. The speedy planet and the two Red Giant stars appear in a nearly horizontal line on the Western horizon with Procyon, Pollux, Castor, and Capella hovering above them. Starting on April 25 and 26, the crescent Moon joins Mercury and the planet is moving ever closer towards the Pleiades. If we have clear skies on the Kenai and an unobstructed view towards the West (Mt. Redoubt) and Northwest (Mt. Spurr), we should be able to see that spectacle.
Up all night is Saturn. Look for a large triangle of bright stars about 20 to 45 degrees above the Southern horizon (in the evening). Those are Leo's Regulus on the right, Virgo's Spica on the left, and Bootes' Arcturus on the upper left. They play host to an intruder, Saturn, of similar brightness as the stars are. Until the wee hours that triangle with Saturn has moved towards the Western horizon.
The other planets can be seen early in the morning, around 6 am, very low on the East to SE horizon: from left to right they are Mars, Venus, even Uranus, and at a distance Neptune and Jupiter. The view from Alaska isn't favorable at all because from our latitudes it seems that those planets are hugging the horizon while the sky is getting brighter. Again, with an unobstructed view, this time towards the East, i.e. the Kenai mountains, one should spot very bright Venus (as we did all winter long in the evening skies) and Jupiter, and perhaps Mars can be seen as well. Uranus and Neptune would need binoculars but being so close to the horizon during almost daylight will render them invisible.
By the way, Venus may be the only bright celestial object visible during summer. But you'd have to try after 3 am, looking NE.
The stars of winter aren’t quite gone yet. But the days are getting noticeably longer. I consider Leo to be the constellation that heralds spring as it becomes very prominent in March, then moves quickly across the sky over the next weeks and by the time it’s out of sight it’s almost summer. Leo is positioned now prominently high above the Eastern horizon and can be pictured facing to the right with the bright star Regulus as the front paw, with a faint mane above its front shoulder, the hind leg to the left, a tail and a back. Saturn is currently returning – retrograding – to Leo after it had had already advanced to Cancer last year. If you have good binoculars, prop your arms on a car roof to stabilize yourself and you might be able to see its rings and probably are able to see its largest moon Titan.
During dusk and shortly thereafter find bright Venus above the Southwestern horizon. Mercury has become a morning planet but only makes for good views for observers on the Southern hemisphere. The same holds for Mars, Uranus and Neptune as all four of these are situated in Capricornus and Aquarius which are constellations that rise hardly above the horizon for observers in Alaska. Jupiter isn’t much better off, however, mainly due to its brightness, it can be glimpsed as a luminous speck low in the South during pre-dawn hours.
Still prominent above the Southwestern horizon find the great constellations of winter centered on Orion with its brightest stars, red Betelgeuse and blue Rigel, its belt and sword containing the Orion nebula, a great target for binoculars; to Orion’s lower left lies Canis Major with the sky’s brightest star Sirius; to its upper left the star Procyon in its imperceptible constellation Canis Minor; to its upper left Gemini with its stars Castor and Pollux; above it Auriga in the shape of a pentagon with Capella (above the edge of the diagram); and to Orion’s upper right is Taurus with red Aldebaran in the arrow head shaped open cluster Hyades and the most prominent open cluster Pleiades.
Venus continues to dazzle in the West but it’s closing in on the Sun, passing it on March 27. Just prior to that an interesting spectacle awaits (see Sky & Telescope, March 2009, p.58, by Tony Flanders): “it should be visible at both dawn and dusk for at least three days centered on March 23rd […] The farther north you live, the longer the period of dawn-and-dusk visibility will be.”
The other naked eye planets, Mars, Jupiter, and Mercury also put on a spectacle as they appear really close to each other in early March – but they are prohibitively low for Alaskan observers.
Comet Lulin (named after an observatory in Taiwan) moves from Leo through Cancer into Gemini during March. Currently it’s at the brink of naked eye brightness, therefore best viewed with binoculars. One should detect a small comet tail.
Around March 5 it’s very close to the Beehive Cluster in Cancer, both looking like a couple of smudges with the Beehive showing more detail, with the first quarter Moon closing in.
Comet Lulin is either a long period comet to return in a thousand years, or on a hyperbolic trajectory – never to return. The more location data the better, in order to determine an accurate orbit of any celestial object in our solar system; currently data are stretching along a half year’s worth of the comet’s orbit (since its discovery in July 2008) which is very little compared to its long orbit, therefore the uncertainty in describing its orbit.
Visit the Challenger Learning Center in Kenai on March 6 for their Star Party, 7-9 pm. Call 283-2000.
The Sky in February 2009
The evening sky finds Ursa Minor in the North with Polaris
at the end of the Little Dipper’s handle as usual 60 degrees above the
horizon, telling us the Kenai’s latitude. East – or to the right
– of UMi lies Ursa Major with the Big Dipper’s handle pointing
toward the horizon and the last two stars in the Dipper pointing toward
Polaris. West – or to the left – of UMi are Cassiopeia in the shape
of a W and Cepheus in the shape of a house. Pegasus and Cygnus with bright
Deneb are visible in the West, and so is the bright star Vega. Furthermore, one
can find the Andromeda Galaxy as follows: getting away from town lights and
using binoculars, look at second base of Pegasus’
In the East find Leo with bright Regulus and a bright intruder, the planet Saturn, rising around 10 pm. And finally, watching a big finale in the South, find the great constellations of winter centered on Orion with its brightest stars, red Betelgeuse and blue Rigel, its belt and sword containing the Orion nebula, a star forming region and also a great target for binoculars; to its lower left lies Canis Major with the sky’s brightest star Sirius – Venus and Jupiter are brighter but they’re planets; to its left the star Procyon in its imperceptible constellation Canis Minor; to its upper left Gemini with its stars Castor and Pollux; above it Auriga in the shape of a pentagon with Capella; and to its upper right Taurus with red Aldebaran in the arrow head shaped open cluster Hyades and the most prominent open cluster Pleiades. When it gets cold and clear, bundle up, have cookies and hot chocolate at hand, and brave the cold to marvel at the best views the Northern hemisphere is offering. Also, if you happen to use hot rum to stay warm, invite me too.
Three special celestial events occur but two of them will be
too hard to see: on February 9 at around 5 am the full Moon enters the
penumbral, that is outer and fainter, shadow of Earth during this lunar eclipse
which is the reason why we probably won’t notice much. During midmonth
Jupiter, Mars and Mercury rise together around 9 am but so does the Sun; this
is mentioned in astronomical magazines and on web sites but they’re
written for the Lower 48 and some such events are not applicable for Alaskan
latitudes. But on February 27, this winter’s evening beacon, Venus, is
joined by the crescent Moon and that is a sight observable from
A book that I recently purchased is called “The Hundred Greatest Stars” by James Kaler. Mind you, a google search for this phrase yields fifty percent astronomical results and fifty percent screen legends.
Anyway, while each star that made the list has some specialty but may be too faint for casual observing, among this list of 101 stars (the author’s count starts at 0 with our Sun), six are bright enough to be seen with the unaided eye.
These are the Sun, Sirius, Vega, Capella, Betelgeuse, and Polaris; all of them mentioned above.
They are yellow, white, white, yellow, red, and white.
They are 0.00002, 10, 25, 40, 400, and 400 light years away, respectively.
They are 1, 20, 50, 130, 50000, and 2000 more luminous than our Sun.
These two sets of numbers together show that Sirius, Vega, Capella, and Betelgeuse may appear of similar brightness: although they are progressively further away, they are truly more luminous which makes up somewhat for their further distance. Indeed Vega, Capella, and Betelgeuse are almost equally bright to us while Sirius shines a little brighter.
Polaris on the other hand must be much fainter: it’s as distant as Betelgeuse is but shines much less luminous. Although both are supergiants, the former would fill only the orbit of Mercury while the latter would extend past Mars’ orbit.
It’s also clear why the Sun appears much brighter: despite being the least luminous of these stars, it’s much, much, much closer. Thus it appears – to our delight and necessity – much, much, much brighter than any other stars.
The specialties of these six stars are: the Sun is our
energy- and ultimately life giving star, getting its energy from fusing
hydrogen into helium; Sirius, a star in its evolutionary stage similar to the
Sun, i.e. considered a Main Sequence star, is the brightest star we can see
(only outshone by Sun, Moon, Venus and Jupiter – all because of their
proximity) because it is relatively bright and relatively close, because it
appears so bright, our atmosphere also make it sparkle the most, and it’s
also the central star for the most studied white dwarf star (a star that went
through all stellar stages and settled as a dead, i.e. no nuclear fusion going
on anymore, star the size of Earth with a mass of the Sun and a composition of
carbon, that is it’s a pure diamond, shining away what little heat is
left; Vega, also an MS star, serves as a standard that all other stars are
compared with, if you think that stars are mostly white, than Vega truly is;
Capella is actually a double or binary star, two dying yellow giants orbiting
each other; Betelgeuse is a dying red supergiant, fusing helium to carbon and
oxygen, and due to its huge size to date the only other star besides our own
Sun whose surface has been photographed (by the Hubble Space Telescope);
Polaris happens to lie very near (within one degree) of the North celestial
pole and therefore serves as a guide for navigation since it yields one’s
latitude instantly.
The Sky in January 2009
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The view is toward Southeast between 7 pm and 10 pm throughout January; because of Earth’s rotation, this part of the sky moves through the South into the Southwest each night all night long. Three constellations are dominating the sky: Orion the hunter, Gemini the twins, and Taurus the bull. This part of the sky is probably the most interesting and brilliant since it contains a number of easily seen deep sky objects as well as eight of the twenty brightest stars. Starting with Sirius, the brightest one of all, on the horizon (to the upper left of the cabin), we go clockwise to Procyon, then the twin stars Castor and Pollux, then yellow Capella (just outside the diagram on top left), then red Aldebaran in Taurus’ arrowhead, and finally close the circle with blue Rigel and red Betelgeuse in Orion.
Aside from stars, there is of course the Orion nebula, a birth place for stars, making up the sword which can be glimpsed with binoculars. We find two prominent star clusters in Taurus, the Pleiades (just outside the diagram on top right) and the Hyades (the arrowhead surrounding Aldebaran) which can easily be seen with the naked eye. Stretching from Gemini up to Capella are four star clusters which need some prodding when using binoculars. Since Gemini and Taurus are also Zodiac constellations, planets regularly move through them, as Mars will do next winter.
Other prominent constellations and stars in the sky are the Little Dipper high in the North, the Big Dipper in the Northeast, Cassiopeia’s W almost in the Zenith (overhead), Pegasus’s Great Square low in the West, and Cygnus’s cross with bright Deneb and next to it bright Vega, both low in the Northwest.
As for the
planets, Saturn rises around 10 pm due East, between bright Regulus in Leo and
Spica in Virgo. Jupiter and Mercury are too low on the Southern horizon to be
seen from
But I have to apologize for not mentioning Venus in last month’s column. You’re likely to have seen it already several times in December, looking Southwest in the early evening, glaring like a beacon. It will continue to shine brightly throughout January and well into March. While checking with my astronomy software I had estimated incorrectly that Venus would be too low on the horizon that it would be hidden by trees. But not so, as it is quite high.
On January 22 you can spot much fainter, greenish Uranus with binoculars to Venus’ left; it will be the very next object to the left, perhaps a fifth of your binoculars’ field of view away from Venus. On the evening before it’s to Venus’ upper left, on the evening after to its lower left – as Venus is moving past Uranus on its much faster orbit around the Sun.
On January 29 and 30 Venus will be joined by the crescent Moon, a repeat of what you also may have noticed around December 30 and 31 – again unannounced due to my lapse.
You can get free sky maps at skymaps.com by clicking on Download Now each month’s Sky Calendar. And if it really is too cold, check out the similar in name web site sky-map.org.
The Sky in December 2008
The chart shows the evening sky during December – 8 pm early and 6 pm late in the month. Stars with an asterisk * attached are marked as dots on the chart.
Still high in the sky, now in the West, is the “summer” triangle, made up of Lyra’s Vega*, Cygnus’ Deneb* - a long necked swan, shown as the northern cross on the chart - and Aquila’s Altair*. From South to North we see several prominent constellations: the great square of Pegasus, also appearing as a baseball diamond with Markab at home base and Scheat, Alpheratz and Algenib on first, second and third base, the W of Cassiopeia with its brighter stars Schedar and Caph, the fainter house of Cepheus, the little and big dippers of Ursa Minor and Major – the small and large bears – and the bear watcher Bootes which is setting in the North. Ursa Minor’s brighter stars are Polaris at the end of the Little Dipper’s handle and Kochab and Pherkad at the end of dipper; to see the remaining four stars in between your eyes need to adjust to the darkness first before they become visible. Ursa Major’s prominent stars are Merak and Dubhe in its dipper which are also the pointer stars for Polaris. Polaris, the North Star, derives its fame of course from being the pole star and therefore very important for navigation: by being within 1 degree of the North celestial pole it determines one’s latitude right away; but a common mistake is to assume that it appears very bright while in fact there are 48 brighter stars seen in the sky. Also in Ursa Major is the double star Mizar and Alcor in the bend of the handle.
Orion, the Hunter, is about to rise. It is many people’s favorite because of its brilliance. Four stars arranged in a rectangle - red Betelgeuse*, blue Rigel*, Bellatrix, and Saiph - outline the body, while three stars make up the belt - Alnitak, Alinalam, Mintaka - with the Orion nebula as the sword beneath it. Above Orion you find Taurus, part of it in the shape of an arrowhead including red Aldebaran*. And above that are the Pleiades* or Seven Sisters, a must for binoculars. To Taurus’ left is the pentagon Auriga with yellow Capella*. Beneath Capella appear Castor* and Pollux*, the twins in Gemini. And then we close this circle towards the horizon, with Procyon and the Number One: Sirius, the brightest star in the entire sky; both of which will rise about two to three hours after Orion.
Around 2 am notice two bright objects standing above the Eastern horizon. The higher one is Regulus, the brightest star in Leo, the lion, a constellation easily recognized as such. The other object is our solar system’s gem, Saturn. In high-powered and stabilized binoculars or in low-power telescopes one can get a hint at its rings and see its brightest moon Titan too. For early risers, watch Orion setting in the West just before dawn. Now Regulus and Saturn appear high in the South with Virgo’s bright Spica following them.
Very bright Venus and Jupiter are out too but since they are in Sagittarius which is very low in Alaska, they are way too close on the Southern horizon around 6 pm; in fact both had a close encounter in early December but it was too hard to watch from Alaska anyway (I had mentioned it in my November column). Mars is on the other side of the Sun. Uranus and Neptune are still possible, however, they’re low in Aquarius and Carpicornus and one needs binoculars and good finder charts (see http://media.skyandtelescope.com/documents/Uranus_Neptune_Findrs.pdf). Mercury is too close to the Sun this month – the next time it could be glimpsed would be late April 2009.
Around December 14, the Geminid meteor shower will be at maximum with up to 75 meteors per hour. However, light from the virtually full Moon will interfere. Still, at that rate it may any year’s best meteor shower, even outdoing the Perseids in August which battle the all too bright Alaskan summer nights anyway. While almost all meteor showers are associated with debris from comets, the Geminids derive from the asteroid Phaeton’s jetsam.
By the way, you can get free sky maps at skymaps.com by clicking on Download Now each month’s Sky Calendar. They’re of better quality than mine too.
The Sky in November 2008
Winter has almost arrived and that means that the bounty of the beautiful winter sky charms us once more. The accompanying chart is set for 10 pm in early and midnight in late November (notice also that South is at lower left), thus more stars will have risen in the earlier evening hours later this month.
Finally the large and interesting constellations of Orion, Taurus, Gemini and Auriga are rising in the East. Within them are the bright stars of winter (marked as large dots): red Betelgeuse and Aldebaran, blue Rigel, yellow Capella and the twins Pollux and Castor. Also included is the star cluster of the Pleiades, best viewed with binoculars through which up to 50 stars may be seen. Around midnight the bright stars Procyon and Sirius will rise in the East. And in the wee hours, around 6 am, Spica in Virgo and Regulus in Leo will have risen – but the more prominent object lies in their midst: brighter Saturn whose rings can nicely be seen in a small telescope.
Back to late evening, we can see Cassiopeia's W and the
House of Cepheus straight up. Always in the same place, 60 degrees above the
Northern horizon, is the Little Dipper with Polaris and toward the Northern
horizon appears the Big Dipper. The kite-shaped Bootes is now setting while the
summer triangle consisting of Deneb (the Swan's tail), Vega and Altair in the
constellations Lyra, Cygnus, and Aquila (harp, swan, and eagle), is getting
closer to the Western horizon but will be visible until January since Deneb and
Vega are circumpolar in Alaska (i.e. they never set).
Saturn is the only planet that can easily be seen this month. Technically,
very bright Venus and Jupiter are there too but since they are in Sagittarius
which is very low in
The Taurid meteor shower occurs during the night of November 4/5 and the
Leonids will show during the night of November 16/17.
A newly published book is “The 50 best sights in Astronomy and how to see them” by Fred Schaaf who also writes the monthly Sun, Moon, and Planets column in Sky & Telescope on which a lot of my information is based. I chose five of the top ten sights to share, none of them require binoculars or a telescope:
#1 the starry sky itself and #7 the Milky Way (the galaxy we reside in), exactly what I present here. All that is needed is an appreciation of dark skies and the stars, constellations, planets, Moon, and Milky Way. If you want to identify objects, use my sky charts or get a better one (e.g. free at skymaps.com).
#3 meteor showers. You need to know when they occur, date and time (either through my column or from other sources). Then just get out, look towards the area surrounding the radiant point, e.g. Taurus or Leo, and be patient for a few minutes – grains of comet dust vaporize in Earth’s atmosphere, heating up so much that you see them glow brightly as they streak by.
#5 the Aurora Borealis, also called Northern Lights. The first web site that I have my browser point at in the morning is spaceweather.com which keeps us current of, among other things, Solar Flares and Coronal Mass Ejections. When they are directed towards Earth and hit our magnetic field a few days later, the charged particles (mostly protons and electrons) are funneled towards the magnetic poles where they collide with molecules (mostly Nitrogen and Oxygen) in our Ionosphere about 100 miles up. Part of the energy released in those collisions is converted to visible light and the colorful displays we see.
#10 the Summer Triangle, see description above.
The Sky in October 2008
The
stars of fall are back: I highlighted easy to find constellations such as the
Big Dipper, the fainter Little Dipper, kite-shaped Bootes, W-shaped Cassiopeia,
house-like fainter Cepheus, cross-like Cygnus, the dashed-line Summer Triangle
(still overhead in early fall), the Great Square of Pegasus, the arrow-like
snout of Taurus, pentagon-shaped Auriga.
I also highlighted the brightest stars with big dots. Although big on star
charts means brighter, no matter how much stars are "magnified" in a
telescope, they're so far away that they still appear as pinpoints. But in
telescopes they appear brighter and perhaps their color shows better,
indicating the surface temperature of a star, ranging from 5000 F for
"cold" red stars, 11,000 F for yellow stars, 20,000 F for white ones
up to 40,000 F for "hot" blue stars.
There are red Aldebaran in Taurus, yellow Capella in the Northeast, the
twins’ white Castor and orange Pollux on the northeastern horizon, red
Arcturus in Bootes - the Big Dipper’s handle points to this star - and
white Deneb, Vega and Altair which make up the summer triangle; the fainter
yellow North star Polaris is designated by the little cross at the end of the
Little Dipper’s handle. To the upper right of Aldebaran, look at the
Pleiades or Seven Sisters. Also of note is Albireo, actually a double
star, at the lower end of the cross with the brighter component showing at a
golden yellow in binoculars and the fainter one being blue.
The arrows show the direction in which the stars seemingly turn around Polaris
- due to Earth rotating in the opposite direction under the stars - with stars
setting in the West and new ones rising in the East.
Aside from these prominent stars and constellations, it’s worth noting
fainter and harder to see constellations. Starting from the Southern
horizon going up towards Polaris I’ll briefly describe Capricornus,
Aquarius, Equuleus, Delphinus, Lacerta and Cepheus. Capricornus and Aquarius
are part of the Zodiac, i.e. our Sun, our Moon and planets and most asteroids
can be found within these twelve constellations. Right now the planets
Neptune and Uranus can be spotted in Capricornus and Aquarius; on how to find
them check out skyandtelescope.com which has some good finder charts (click on
“Celestial Objects”, then “Planets”). I waited and
waited throughout September for a clear evening and I was just able to get such
an evening about a week ago, on which I easily found Uranus with binoculars
(and aforementioned finder charts) from my porch; however, Neptune eluded me
mostly because Capricornus is really low on the horizon and a darker sky than
the one provided on K- Beach is needed.
Back to the constellations, Equuleus means "little
horse" and consists mainly of four dim stars half way between
Jupiter in Sagittarius is almost too low on the Southern
horizon (although you may try early evening with an obstructed view, e.g. over
Cook Inlet from the northern
The Sky in September 2008
This month may be the best to find Uranus and Neptune, two faint planets that can be seen with binoculars. My chart gives you a general idea of where they are around midnight, especially in relation to the prominent Summer Triangle (pictue everything further left if you observe earlier in the evening). But you also need more detailed charts for which this link may work best: http://media.skyandtelescope.com/documents/Uranus_Neptune_Findrs.pdf (I don’t reproduce these charts because of their copyright). Both planets should be high enough, 25 and 15 degrees respectively above the Southern horizon, when observing with few trees obstructing the view.
Jupiter is out but very low in Sagittarius in which it climbs to a maximum height of only 7 degrees (in December and January the Sun is Sagittarius and that’s why it is very low on the horizon). Saturn is in superior conjunction, i.e. on the other side of the Sun, and therefore cannot be viewed until October prior to dawn. Mars, Venus, and Mercury appear very close together – however, in Alaska they’re setting on the Western horizon around the same time the Sun does.
Now we are able to actually see
stars in once again dark environs; the following description holds for all
evenings in September. To first orientate yourself find the Big Dipper low
in the Northwest; then extend the dipper's last two stars high into the North
to find Polaris, the North Star, and the Little Dipper; with the Big Dipper on
one side of Polaris, find the constellation Cassiopeia, a nicely shaped W, on
the other side of Polaris high in the Northeast. Back to the Big Dipper,
follow the curve of its handle towards the bright Red Giant Arcturus low in the
West with its constellation of Bootes above, appearing as a kite or cone
shape. Notice the bowl shaped Corona Borealis to its upper
left. Prominently high overhead and extending to the South is the Summer
Triangle, made up of the three bright stars Vega, Deneb and Altair. Deneb's
constellation of Cygnus, the Swan, in a cross shape is easily seen; Vega's
small rectangular shaped Lyra, the Harp, is prominent as well; while Altair's
Aquila or Eagle may be depicted by its wings. But just on the upper left
of Altair is the dolphin shaped small constellation Delphinus. Also
prominent in the Southeast are the Great Square of Pegasus and low in the
Northeast bright yellowish Capella with its pentagon shaped constellation
Auriga. By morning constellations have rotated towards the West with some
of them having set while others have risen in the East. Those are Orion,
Taurus, Gemini, Cancer and Leo as well as the planets described above.
Have fun observing: I'm looking forward to hopefully clear
skies this winter and the online Astronomy class I'm teaching this fall
semester.
When teaching Astronomy, I use the German pronounciation for Uranus, so as to avoid the snickering and distractions from the concepts. However, while learning the planet names with my 3-year old (the planets hang on his room’s ceiling) every time we come across Uranus I instruct him to laugh. Being a smart guy he questions that every time – because in German there’s no reason to laugh.
The Sky in April 2008
Days are getting longer and nights are getting shorter. We're
also leaving the freezing cold behind. As we all love winter's benefits,
we surely regret that our beloved starry skies will take a back seat soon.
But at least we get some nice views for a good-bye. With
Daylight Savings Time having started early last month, it doesn't get dark
until 10 pm or even later and therefore the diagram shows the Western sky around 11:30 pm towards the end of April.
This late in the season, many of the brilliant stars of winter are either gone
or hard to detect. Therefore look early in the month in the West for Sirius and
Orion with Betelgeuse and Rigel, Aldebaran and the Pleiades. Still visible all
month are the twins Castor and Pollux in the middle of the diagram, Procyon
below and left of middle, Capella in its pentagon of Auriga on the right. But
look out especially for Mars which has now moved towards the left (East) of
these bright stars; around May 5 (Cinquo de Mayo, Korean Children’s Day)
it exhibits a perfect straight line with Gemini’s Castor and Pollux.
Having shifted from East to West throughout late winter are Leo with Regulus and Saturn nearby. The latter is actually of virtually the same brightness as those bright stars I described and thus blends in pretty good, showing an acute triangle with Regulus and Algeiba in the lion’s mane.
Saturn looks great in binoculars and in telescopes of all sizes. Take a peek and see the Southern side of the rings for the last time since the mid nineties: next year the rings will be edge-on, i.e. sometimes appear invisible, then the Northern side will open up the following year, lasting for half of Saturn’s orbit until the mid twenties. This effect happens because Saturn’s rings are tilted by 20 degrees with respect to its orbit and next year Saturn appears in the part of its orbit where they’re edge-on.
Mercury can be barely glimpsed after sunset in late April and early May, also see diagram.
The other planets are not viewable for various reasons: Venus is on its way towards superior conjunction, i.e. on the other side of the Sun; Jupiter resides in Sagittarius which is a pretty constellation but too low when viewed in Alaska (Jupiter may appear very low near the Southern horizon during dawn); Uranus and Neptune are too close to the Sun, they may be viewed again in early fall.
The crescent Moon appears just left of the Pleiades on April 8 (the East coast sees the Moon occulting the Seven Sisters). On April 11 the half Moon sits right on top of Mars, and this should be interesting to watch throughout the evening and night: first it will be pretty, second, by viewing the Moon during daylight, one might be able to glimpse Mars with binoculars to its lower left, and third, the Moon’s West-to-East motion becomes apparent when it glides to Mars’ left throughout the night. On April 14, the now gibbous Moon joins Saturn and Regulus; on April 18 the full Moon is near the bright star Spica in Virgo; on April 27 the half Moon sits very low on the Southern horizon during dawn with Jupiter right above it.
In the East find Arcturus by following the Big Dipper’s handle, in the Northeast Vega, Deneb and Altair are becoming more prominent. They can be seen all summer during the few hours of semi-darkness and are aptly named the Summer Triangle.
The Sky in March 2008
The hunter Orion, with
its brightest stars Betelgeuse and Rigel, stands above the horizon, hosting the
Orion Nebula a nice target for binoculars. To its lower left is the brightest
star that we can see from Earth, Sirius that's the one we've been seeing
prominently on the southern horizon for the past month when driving on the
Kenai Spur Highway or on Kalifornsky Beach Road toward Soldotna in its guide
dog, Canis Major.
Procyon in Canis Minor
is to its left, Castor above Pollux in Gemini to its upper left Castor itself
is a fine triple star in small telescopes Capella close to the zenith and this
host of great stars rounded it out by the bull's Aldebaran and the Pleiades
seven sisters, Subaru in Taurus.
Quite a bit to the left
of these constellations and stars are Regulus and Saturn, whose rings can be
seen in a small telescope. The asteroid Ceres, currently in Taurus, can be
glimpsed with binoculars but one would need a good finder chart, for example
published on Sky & Telescope's Web site.
But mostly it's Mars
standing out among all these stars. Unfortunately, it's not a greatest target
because only its reddish color and its disk can be seen in binoculars or a
small telescope.
The crescent moon will
be near the Pleiades on March 11, the now half moon near Mars on March 14, near
the star cluster Praesepe also called Beehive on March 16, and the full moon
near Saturn on March 18 and 19.
Other stars visible are
parts of the "summer" triangle, namely the bright stars Deneb and
Vega just above the Northern horizon; because we're so far North, the summer
triangle is visible during Alaska winters as well.
Arcturus rises in the
east; besides being a bright star, it can also be found by following the Big
Dipper's handle, which is curving toward it.
Daylight savings time
begins on March 9. The spring equinox occurs on March 19, by definition, this
is when day sunrise to sunset and night are of equal 12-hour lengths. Because
we're so far West in our Alaska time zone, the "noon" sun will then
appear at 2 p.m. with sunrise at 8 a.m. and sunset at 8 p.m.
The diagram was created
with the free software Stellarium. I put the moon in the picture because its
light illuminates the foreground snow and trees.
The Sky in February 2008
The Sky in January 2008
The
starry sky is now at its best with the most prominent stars being well placed
high in the South: blue Rigel and red Betelgeuse in Orion, Sirius beneath it,
Procyon to its left, Pollux and Castor higher up, Capella almost in the Zenith,
and Aldebaran and the Pleiades completing the splendor.
However, even better situated is Mars as it’s centered among some of the
above mentioned stars, e.g. it can be seen surrounded by Pollux, Capella,
Aldebaran, and Betelgeuse, all of them in the shape of a star or cross.
The Big Dipper starts out close on the Northern horizon but Cassiopeia,
Perseus, and Andromeda are close to the Zenith. In the West Cygnus and Pegasus
are about to set while bright Vega, being circumpolar in Alaska, stays close to
the horizon.
Saturn rises in the evening together with Leo’s Regulus, trailing Gemini
and Cancer low in the East.
The chart shows the sky around 10 pm in early January and 8 pm in late January.
I inserted grid lines showing the altitude at 30, 60, and 90 degrees, and the
azimuth also in increments of 30 degrees, starting from North. I chose not to
show all constellations – e.g. faint constellations Eridanus, Cetus,
Pisces, Aquarius in the Southwest are missing – because the chart is
already crowded enough.
Venus might still be glimpsed for most of the month during early mornings in
the East. Jupiter and Mercury are too low on the horizon for Alaskan observers.
The crescent Moon appears around the tenth low on the SW horizon, then makes
its way as a first quarter and waxing gibbous Moon across the aforementioned
faint constellations during the following week. As a full or almost full Moon
it spends January 20-25 in Taurus, with Mars, in Gemini, and then with Saturn.
On January 19, our Moon will occult Mars (move in front of it): look for a
virtually full Moon just 5 degrees above the horizon around 1:30 pm, i.e.
during broad daylight but it’s easy to spot the Moon if it’s not
cloudy. Look at it with binoculars and you might see Mars to its lower left.
Between 1:45 pm and 2:15 pm it will slide in front of the red planet, then Mars
can be seen at our Moon’s lower right.
2008 will be another leap year. Why?
An Earth year is based on Earth appearing in the same spot in its orbit. That
time however is not an integer multiple of an Earth day, but instead lasts
365.2425 days. The decimals are close to 1/4 and can be added up to 1 full day
after each 4 years; so we have a leap day (February 29) every four years.
Basically that’s all we need to know for our life times. But if our very
young children get to live to an old age, they will see that between the leap
years 2092, 2096, 2104 and 2108, the year 2100 is skipped – because .2425
is not quite 1/4, some leap days need to be skipped (3 total in 400 years).
That’s the achievement of the Gregorian calendar: to keep the seasons in
synch with the calendar as we know. That’s also why the revised Julian
calendar used by Orthodox churches differs by 13 days.
Something about calendars: how often can calendars be recycled? That depends on
how they follow a leap year: the calendar after a leap year, e.g. 2005, can be
used again 6 years later, in 2011; the calendars two and three years after a
leap year, e.g. 2006 and 2007, have to wait 11 years, until 2017 and 2018; the
leap year itself, e.g. 2008, can only be used in its entirety 28 years later,
in 2036. If you happen to come across a 1980 calendar, notice that it will be
accurate this year.
These actually simple calculations are based on the calendar advancing by one
week day each year, e.g. January 1, 2007, was a Monday and January 1, 2008, is
a Tuesday. (52 weeks of 7 days make 364 days, supplying 1 extra day [compare to
the 365 days in a year mentioned in the previous paragraph].) So in counting
one up each year (two for a leap year), one figures that after 7 counts (or 14,
21, 28) the week day appears the same and a calendar can be reused. Sometimes
though the leap year completes the count to 7 or jumps over it and therefore
recycling takes longer.
The Sky in December 2007
The recurring spectacle starts between 7 and 8 pm every
day in December. That's when a brilliant winter sky starts rising in the
east: along with Orion's Betelgeuse and Rigel, its belt and sword, Canis
Major's Sirius and Canis Minor's Procyon, Gemini's Castor and Pollux, Cancer's
Praesepe cluster, Auriga's Capella, Taurus' Aldebaran, Hyades and Pleiades
clusters, the planet Mars glows reddish among them. Mars is closest to Earth on
December 18 at 54 million miles but of course presents great views all month
long. Together with the two two red giant stars Betelgeuse and Aldebaran, Mars
is producing a great triangle.
Somewhat later in the evening Leo's Regulus and the planet Saturn are rising.
To include those two the diagram shows the sky around 11 pm when everything
moved to the South. I used the free shareware "Stellarium" and the
snow covered mountains are actually the Olympic Range in Washington as a
possible landscape in the software.
The full Moon can be seen very close to Mars on the 23rd, the waning thrid
quarter Moon is close to Saturn on the 27th and 28th.
Looking elsewhere in the early evening, but not pictured in the diagram are the
constellations and stars in the North: Ursa Major above the horizon, Ursa Minor
quite high; in the West: Cygnus' Deneb, Lyra's Vega, Aquila's Altair,
Delphinus; near the Zenith: Cassiopeia, Cepheus, Pegasus, Andromeda, and
Perseus.
Venus remains the main staple in the morning sky, rising around 8 am in the
East. If you happen to drive East on the Sterling Highway at that time, it's
Venus that you see; it appears together with a waning crescent Moon on the 4th.
The other planets, Mercury, Jupiter, Uranus, Neptune, and Pluto, are either on
the other side of the Sun or lost in the glare of twilight.
The Geminid meteor shower peaks during the nights of December 13 and 14 with an expected average of about 20 meteors per hour; the radiant - as the name suggests - lies in Gemini, so it looks as if the meteors are emanating from Castor, Pollux and Mars. It's also the only major meteor shower that is associated with an asteroid, Phaethon, rather than a comet.
Comet 17P/Holmes is still a faint fuzz ball near Perseus' brightest star Mirfak, between Auriga’s Pentagon and Cassiopeia’s W and can be spotted with binoculars (for finder charts I recommend skyandtelescope.com).
While the winter solstice occurs as expected on December 22, the earliest sunset is already on the 8th and the latest sunrise on January 5. Since Earth is closest to the Sun on January 3 at 91.5 million miles (it's farthest on July 4 at 94.5 million miles), it orbits a little faster - this has to do with Kepler's second law, which is due to the conservation of angular momentum, and which is also responsible for a figure skater to spin faster upon pulling in his arms during a pirouette - and therefore the day (from one noon to the next noon) is at 24h 00m 28s about half a minute longer than the average day (by definition 24h 00m 00s). Since clocks are kept at a these constant 24 hours, this combined effect places the earliest sunset two weeks earlier than the solstice and the latest sunrise two weeks later.
The Sky in November 2007
Winter has almost arrived and that means that the bounty of the beautiful
winter sky charms us once more. The accompanying chart is set for 10 pm in late
November, thus fewer stars are visible in the East during evening hours earlier
in the month (but more in the West); stars with an asterisk * attached to them
are marked with a letter on the chart. Orion, Taurus, Auriga and Gemini
are visible in the Southeast. Inside these constellations are the bright
stars of winter: red *Betelgeuse and *Aldebaran, blue *Rigel , yellow *Capella
and the twins' *Castor and *Pollux; the latter two make a fine triangle with
Mars. Also included is the star cluster of the Pleiades, best viewed with
binoculars when up to 50 stars may be seen. Soon the bright stars Procyon
and Sirius will follow. Now near the Zenith are Cassiopeia's W, the House
of Cepheus, Pegasus’ Great Square and the swan Cygnus’ northern
Cross.
Always in the same place is the Little Dipper with *Polaris and atop the
Northern horizon appears the Big Dipper. The kite-shaped Bootes with red
Arcturus is now setting while the summer triangle consisting of *Deneb (the
Swan's tail), *Vega and *Altair is getting closer to the Western horizon.
Mars rises around sunset. Planets move counterclockwise in the Solar
System – when viewed from North – which produces their true West to
East motion along the ecliptic and through the Zodiac constellations as seen
from one night to the next. But when the Earth, and we as the observers on
Earth, pass a planet, that planet seems to move in the opposite direction: it
retrogrades. From November through January it’s really easy to see Mars
retrograde – which is mostly evidence for us passing Mars – because
there are three stars situated near that are of comparable brightness. In the
process of us passing Mars, the red planet becomes also brighter to the naked
eye and appreciable larger in a telescope until it reaches opposition on
December 19. Observe Mars weekly or even daily: it can be seen to the right
(West) of Castor and Pollux in Gemini, moving East-West (left-to-right) towards
red Aldebaran in Taurus (with the Pleiades further West). The triangle formed
by Castor, Pollux and Mars becomes ever more elongated from mid-November
through December until Mars stops retrograding in late January – now
quite a bit closer to Aldebaran – when we have passed the planet enough
that we see its true motion again. Mars is flanked by the almost full Moon on
the 25th (see chart) and 27th of November, on the 26th Mars sits right beneath
it.
Jupiter would be visible very low in the Southwestern sky during dusk, but only
in the Southern United States.
Pluto, Neptune and Uranus are too low in the sky as well to be observable from
Alaska.
Saturn and Venus are visible during dawn, having developed into a line with
Leo’s Regulus: from midnight on throughout the rest of the night find
Regulus leading Saturn in the East, then around 5 am Venus rises and you can
use it to find the now higher situated star and ringed planet. And since Alaska
nights get longer every day, you’ll see Venus during your morning
commutes, if you’re heading East. On November 5 a crescent Moon is
near Venus.
Mercury is also visible during early November in the dawn sky: between 7 am and
8 am – as you’re enjoying dazzling Venus, connect an imaginary line
diagonally to the lower left from it towards the horizon: you should be able to
see Mercury very low on the Southeastern horizon. In fact, the similarly bright
star Spica is just to the right of it, so look for “headlights”
beneath Venus, though Venus is quite a beacon compared to those headlights. On
November 7 a very crescent Moon joins Mercury and Spica. Towards the middle of
the month Mercury has moved along, seemingly back towards our Sun, now producing
a long, slightly curved line with Spica and Venus. Try finding this speedy
planet as few people have consciously seen the planet as such.
The Leonid meteor shower peaks in the wee hours of November 18th with an
expected average of about 10 meteors per hour.
Comet 17P/Holmes came as a nice fuzz ball into view; it was the 17th periodic
comet discovered and recognized as being periodic (1P/Halley was the first) by
Edwin Holmes in 1892, with a seven year orbit that brings it as close as
Mars’ orbit and as far as Jupiter’s orbit. Use binoculars and look
half-way between Auriga’s pentagon and Cassiopeia’s W, the comet is
about as bright as the surrounding stars.
The Sky in October 2007
As research for my astronomy columns I'm reading "Celestial Delights -
the best Astronomical events through 2010" by Reddy and Walz-Chojnacki,
some specialized information if I talk about a certain subject, and I study the
“Starfinder” (a simple cardboard sky map that tells us where the
stars are at any time during the night on any day during the year, every year).
But I prepare especially by perusing the future issues of "Sky &
Telescope" and "Astronomy". With "future" I mean that
the November issues are about to hit the stores by the time you read this
October article. Unfortunately all weekly and monthly periodicals publish their
newest issue with a future date that still may be a month out and they are
therefore pretending to be super-current (they're not). But just about the only
magazines for which this is justified are astronomy related ones because they
publish highly predictable events with the intent that readers would know about
them a few weeks ahead of the fact. Ditto my monthly column.
So when I prepare my columns I carefully read through “Sky &
Telescope” and then I don’t do this: plagiarize. Plagiarism is
unethical, unlawful, and university professors hand out Fs for the course work
if a paper was plagiarized. But besides that, I can’t even do it. I
cannot take somebody else’s work and retype it. I just like my own
sentence structure that’s distinctly me, including my German accent. In
fact, after I have read through my sources, I put them aside and then I write
my own narrative, frequently checking the sources for exact dates. So when I
write that we will have a full Moon on October 25th at 8:52 pm, then even my
facts are markedly different from the source (“The Moon is full at 12:52
a.m. EDT on the 26th”, S&T, October 2007, p.55), yet - of course -
still similar since it’s about the Moon, it’s full, it’s in
October and there are only a handful of ways to write about that in a coherent
sentence.
After this long introduction (and I’m not done with the introduction) I
figured I’d stray from my usual narrative and instead reiterate the
information printed in S&T; you may compare. Please note that these are
still my own words since I use a different way of writing (S&T has the
luxury of using 23 pages to report on upcoming celestial events and
observations while I’m restricted to half a page; I’m also using
more parentheses).
During dawn on October 7 and 8, Saturn and Venus as well as the bright star
Regulus in Leo and a waning crescent Moon shine low in the East (see the
diagram, made with the shareware Stellarium). During the following days those
two planets and star are really close to each other while our Moon moves on
toward its monthly encounter with our Sun. On the 15th the now waxing crescent
Moon meets Jupiter and Antares in Scorpius; however, this crescent as well as
the 1st quarter Moon are very low on the Southern horizon – you may have
seen the same scene in mid-September. The Orionid meteor shower takes place
from October 20th through 22nd – its meteors can be seen anywhere in the
sky, originating from their vantage point in Orion, high in the South. On
October 25 we’ll have the largest full Moon of the year because it is
also near its perigee at a distance of only 220,000 miles compared to an
average 240,000 miles. On October 28th, Venus is at 46 degrees at its farthest
from our Sun and has by now become a mainstay in the Eastern dawn sky through
January 2008.
During October evenings the Summer triangle consisting of Cygnus, Aquila and
Lyra (cross, eagle, small harp) are high in the South, the East harbors Pegasus
and Andromeda (great square, two curved rows of three stars each), the North
the Little and the Big Dipper, the West Bootes (kite), and Cassiopeia (a W
shape) may appear near the Zenith. Bright Jupiter may be found close to the
Southern horizon.
Mars becomes visible shortly before midnight, rising in the East. Through April
2008 it moves and retrogrades between Gemini and Taurus. Mainly look for a
reddish object appearing between two bright stars and the bull’s snout
with also reddish Aldebaran and the Pleiades.
Finally, last week marked the 50th anniversary of the first man-made satellite
orbiting Earth, Спутњик (same
pronunciation of the ‘u’ as in “butchered”), launched
on October 4, 1957. These days, if you’re standing outside for just an
hour or so staring up, you’re bound to see a few artificial satellites
moving across the sky.
The Sky in August and September 2007
Stars can actually be seen again, so it's time to resume my Astronomy column. I usually write a September article but since there is a Total Lunar Eclipse visible from Alaska during the night of August 27/28, Monday to Tuesday, it makes more sense to have it published one week early.
This is not the perfect lunar eclipse - it's after midnight, our Moon sits very low above the Southern horizon, and you never know about the weather on the Kenai. But the largest land mass on Earth that can view the entire eclipse is Alaska. Front seats are also reserved for the US and Canadian West coast and Eastern Australia and New Zealand. The only other mammals to see this gorgeous event are Pacific whales and dolphins. However, the entire rest of North and South America can at least view the latter part of the eclipse prior to dawn.
But back to Alaska. The full Moon starts to enter Earth's shadow at midnight but since so much sunlight still reaches our Moon, we won't notice until 1 a.m. Then our Moon enters Earth's umbral shadow, meaning that it now becomes more and more totally eclipsed by Earth's shadow. Totality lasts rom 2 a.m. to 3:20 a.m. - our Moon won't be entirely dark because Earth's atmosphere refracts sun light onto it, most strongly red, that colors our Moon copper-red. Then our Moon starts leaving Earth's shadow and the eclipse concludes at 5:20 a.m. when we get the fully illuminated Moon back.
If it's cloudy or if you're too tired to stay up that early, don't despair. While our Moon will go through its phases six times during the next six months - its amount of lit and dark surface entirely due to its place in its orbit where more or less sunlight is reflected to Earth - another total lunar eclipse is in store on February 20/21, 2008, visible in its entirety from Alaska as well.
As far as observing goes, viewing this lunar eclipse with your unaided eyes from your backyard will be just fine. Binoculars or a telescope are not necessary, though they may show some interesting features.
By the way, lunar eclipses are always accompanied by one or two solar eclipses, either 14 days prior or later. However, neither of the upcoming solar eclipses are observable from North America as the partial solar eclipse of September 11, 2007, is seen from South America and Antarctica, while the annular solar eclipse of February 7 is visible from Antarctica, Australia and New Zealand.
Now let's look at the stars that become visible this month. High in the South is the Summer Triangle made up of Vega, Deneb - in the cross-like constellation Cygnus - and Altair. High in the East are the Great Square of Pegasus and Andromeda, of course containing the Andromeda Galaxy which can be found with binoculars. I figure that it would be too arduous to describe here how to find it without producing another more detailed finder chart; therefore I refer the reader to http://www.greenwich-observatory.co.uk/andromeda.html. Stretching along the Southern and Eastern horizon are the Zodiac constellations Capricornus, Aquarius, Pisces, Aries, and finally Taurus. The first three, Cap, Aqr, Psc lack bright stars and distinctive shapes and are very close to the horizon, hence they are more difficult to observe from Alaska. Our Sun will reside in these constellations as well as in Scorpius and Sagittarius during winter and one can see why our Sun hugs the horizon during winter months. Neptune and Uranus can be glimpsed in Capricronus and Aquarius; finder charts are available at http://www.rasnz.org.nz/SolarSys/UranNept.htm - just hold them upside down because it's a New Zealandian web site. Sky & Telescope has finder charts in their July 2007 issue but unfortunately not online. Perhaps it advantageous to find them during the night of the lunar eclipse, because Uranus resides the same distance to the left of our Moon as Neptune resides to its right.
Towards the East Taurus with the splendid star cluster of the Pleiades becomes visible - more about that when we get into winter - as well as Mars which is hosted by both Taurus and Gemini throughout this winter. Low in the Northeast is Aquila with bright Capella, the first star announcing fall. The Big Dipper, part of Ursa Major, appears in the North. Its pointer stars in the bowl are used to find the North Star, because they point at it. Polaris itself is at the end of the Little Dipper's handle. On the opposite side are the W-shaped Cassiopeia and the house-shaped Cepheus, albeit somewhat fainter. Back to the Big Dipper, we can use its handle's curvature to find bright Arcturus in the West and at the bottom of kite-shaped Bootes. To its left are Corona Borealis and Hercules.
During pre-dawn and dawn, very bright Venus may be glimpsed low in the East - if you drive East on the Sterling highway during the wee hours, that's what you see. And halfway between Venus and the Eastern horizon are Saturn and Leo's Regulus shining like faint headlights - however, the Kenai Mountains in the East probably obscure that view.
The Sky in April 2007
Days are getting longer and nights are getting
shorter. We're also leaving the freezing cold behind. As we all love
winter's benefits, we surely regret that our beloved starry skies will take a
back seat soon.
But at least we get some nice views for a good-bye. With
Daylight Savings Time having started, it doesn't get dark until 10 pm or even
later and therefore the diagram shows the Western sky around 11 pm towards the
end of April. This late in the season, many of the brilliant stars of winter
are either gone or hard to detect. Therefore look early in the month in the
West for Sirius and Orion with Betelgeuse and Rigel, Aldebaran and the
Pleiades. Still visible all month are the twins Castor and Pollux in the middle
of the diagram, Procyon below and left of middle, Capella in its pentagon of
Auriga on the right and, having shifted from East to West throughout late
winter are Leo with Regulus and Saturn nearby. The latter is actually of
virtually the same brightness as these bright stars and thus blends in pretty
good, so you would need this diagram or a starfinder to locate Saturn.
Visible after sunset for about two hours is very bright Venus in the West and since it will stay there all summer, it will probably be the only heavenly object – aside from our Moon of course – that is easily spotted in our lit Alaskan night skies. When viewing Saturn with binoculars look for its rings and its largest and brightest moon Titan.
Jupiter appears in the night sky too but it’s in the Southern portion of the constellation of Ophiuchus which is near Scorpius and since Scorpius is such a low Zodiac constellation, Jupiter also appears very low on the Southern horizon around 2 am.
The other planets are currently too close to the Sun and it’s very hard to view them, especially since they only appear during our long dawn hours.
In the East find Arcturus by following the Big Dipper’s handle, in the Northeast Vega, Deneb and Altair are becoming more prominent. They can be seen all summer during the few hours of semi-darkness and are aptly named the Summer Triangle.
I could talk about the pros and cons of Daylight Savings Time but I don’t want to start a discussion that may be futile. Just this much: local noon is actually at 2 pm on the Kenai when the Sun is highest and local midnight at 2 am.
Instead I figured I’d talk about religious feasts that are based on astronomical observations of our Moon’s phases – not that that wouldn’t start a discussion.
The Islamic calendar is completely based on the lunar cycle with 12 months, i.e. about 354 days long, each starting with the first sighting of the lunar crescent after the new moon, from Muharram to Dhu al-Hijjah. That’s on average 11 days shorter than the solar based Gregorian calendar, so on it Islamic holy days are seemingly shifting by 11 days every year, although within the Hijri calendar itself they are celebrated on fixed days. The first year started in GC 622 with the Hijra (withdrawal of Muhammad from Medina), so we now have 1428 AH with Ramadan – the 9th month – starting on September 12 (new moon will be September 11) and ending on October 11.
The Jewish calendar is based on the lunar cycle with 12 months basically alternating between 29 and 30 days (our Moon needs 29.53 days to go through its cycles), each starting with the new moon, from Nisan to Adar. That means each lunar year is about 11 days shorter than a solar year, so about every third year contains a leap month, Adar II with 29 days. Because that’s still a little too short, leap years are still more frequent (calculated by year modulus 19 as years 0, 3, 6, 8, 11, 14, and 17), hence the “about”. The equivalent in the Gregorian calendar to the Jewish calendar’s first month Nisan is either March or April. In GC 2007 (JC 5767), 1 Nisan is March 20 (new moon was on March 19) and with the Passover always beginning on 15 Nisan, that would be April 3; of course Jewish days start at sundown, so Pesach (Passover) lasts from April 2 through April 9 or 10.
The Christian calendar, more commonly called the Gregorian calendar, is based on the solar year. The date of Easter is computed by figuring out the beginning of spring, i.e. the vernal equinox, figuring out the following Full Moon and then the upcoming Sunday. That’s the basic computation to compute this date on a computer, hence the official name of Computus which derives from the Council of Nicaea. This year’s spring equinox happened on March 21, the next full moon is on April 2 and the next Sunday is April 8.
By the way, the full moon on April 2 is the smallest of the year since our Moon happens to be near its apogee at 255,000 miles, the farthest point from Earth in its orbit, compared to an average 240,000 miles.
Thanks go to Marion Yapuncich who directed me to the free software Stellarium with which my image was generated and to Barb Christian who inspired me with the idea for this month’s topic.
The Sky in March 2007
The stars of winter aren’t quite
gone yet. But the days are getting noticeably longer. I consider Leo to be the
constellation that heralds spring as it becomes very prominent in March, then
moves quickly across the sky over the next weeks and by the time it’s out
of sight it’s almost summer. Leo is positioned now prominently high above
the Eastern horizon and can be pictured facing to the right with the bright
star Regulus as the front paw, the hind leg to the left, a tail, a back and
above the right shoulder with a faint mane. An interloper may add some
confusion though to its outline: Saturn resides in or near Leo through 2009. If
you have good binoculars, prop your arms on a car roof to stabilize yourself
and you might be able to see its rings and probably are able to see its largest
moon Titan.
During dusk and shortly thereafter find bright Venus above the Southwestern horizon. Mercury has become a morning planet but only makes for good views for observers on the Southern hemisphere. The same holds for Mars, Uranus and Neptune as all four of these are situated in Capricornus and Aquarius which are constellations that rise hardly above the horizon for observers in Alaska. Jupiter isn’t much better off, however, mainly due to its brightness, it can be glimpsed as a luminous speck low in the South during pre-dawn hours.
Still prominent above the Southwestern horizon, find the great constellations of winter centered on Orion with its brightest stars, red Betelgeuse and blue Rigel, its belt and sword containing the Orion nebula, a great target for binoculars; to Orion’s lower left lies Canis Major with the sky’s brightest star Sirius; to its left the star Procyon in its imperceptible constellation Canis Minor; to its upper left Gemini with its stars Castor and Pollux; above it Auriga in the shape of a pentagon with Capella; and to Orion’s upper right Taurus with red Aldebaran in the arrow head shaped open cluster Hyades and the most prominent open cluster Pleiades.
Every half year Earth enjoys a couple of eclipses. A total eclipse of our Moon is visible from everywhere in the world, except Alaska. Canada and the Lower 48 are able to see it while in progress on the East coast or being almost done on the West coast. A partial solar eclipse follows on March 19, being visible from most of Asia. Due to the international dateline, it can be observed on March 18 in the late afternoon just before sunset from Barrow and Prudhoe Bay. Use welder’s glasses but you must not use binoculars; welder’s glasses and discarded CDs are safe for naked eye observations but become dangerous when used together with other optical equipment.
I wish I had the time to write an Astronomy column every day. But while holding down a serious and respectable full-time job, it’s hard to compete with astrologers, getting paid to make up stuff. I assume that from a reader’s perspective, horoscopes are nice entertainment, just as I read the cartoons and Dear Abby on the same page and do the Soduko. I wonder how it looks like from the astrologers’s side, maybe it’s a hard job after all, since inventing short stories does require quite a bit of creativity.
Anyway, I figured that I’d try myself on casting some horoscopes. Here they are; of course, the dates refer to the correct definition of the Sun entering and leaving a constellation. Aries (4/18-5/12): in the morning you’re likely to get up, in the evening you’re probably going to rest. Taurus (5/13-6/19): the stars in the Hyades clusters move toward the same vantage point. Gemini (6/20-7/19): this is hard. I admit, that astrologers do have a tough job, pulling adjectives and nouns out of thin air. Cancer (7/20-8/9): my situation of concocting bon-mots hasn’t improved. Leo (8/10-9/15): well, hm, … Okay, I got it. You’ll be surprised to see a bright object in your constellation. Then again, if you have read my astronomy column, you won’t be surprised. Virgo (9/16-10/29): you have a more rigid, theory-oriented approach to life. You are very organized. Libra (10/30-11/22): if you have kids, they will want to play. Be aware that they’ll refuse to go to school today. Scorpius (11/23-28): travel South. Then look out for something new and something really big. In fact, currently Jupiter resides in your constellation and a bright Nova has popped up. Ophiuchus (11/29-12/16): beware the ides of March. Advise to the wise: carry snakes. Sagittarius (12/17-1/18): three square meals, possibly served on round platters, are awaiting you today. Capricornus (1/19-2/14): what’s a sea goat? Aquarius (2/15-3/10): you are poetic, on the other hand, you know nothing of the scientific world (yep, that must be me). Pisces (3/11-4/17): you possibly will celebrate a birthday this month. I cast the bold prescience that it will be confined between 1 and 99.
As an exercise of applying the scientific method to outrageous claims, I had a couple of classes (about 25 students) in the past year try to match up horoscopes blindfolded. The success rate was at 10-15%, slightly higher than the expected 8% random match. (“Slightly higher” shouldn’t be taken as encouragement for the accuracy of horoscopes as there is still a failure rate of 85-90%.)
The Sky in February 2007
The diagram shows the sky on the
Western horizon on February 7 at 6:00 pm. Early February is the best time this year
to view Mercury. You can bracket observations around the 7th, perhaps from the
4th through the 12th. Here’s how to find Mercury: start during dusk,
about 20-30 minutes after sunset (5:20 pm progressing to 5:40 pm during that
time frame); find bright Venus close to the horizon in the general direction of
where the Sun just set, i.e. Southwest; from there Mercury is a little closer
to the horizon. Don’t wait too long during the evening because both
Mercury and Venus get ever closer to the horizon, are thus harder to see, and
set at 7:20 pm and 8:00 pm, respectively. After dusk find the Great of Square
Pegasus above Venus and Cygnus further West; perhaps the cute constellation of
Delphinus still shows up.
The evening sky finds Ursa Minor in the North with Polaris at the end of the Little Dipper’s handle as usual 60 degrees above the horizon, telling us the Kenai’s latitude. East – or to the right – of UMi lies Ursa Major with the Big Dipper’s handle pointing toward the horizon and the last two stars in the Dipper pointing toward Polaris. West – or to the left – of UMi are Cassiopeia in the shape of a W and Cepheus in the shape of a house. As mentioned above, Pegasus and Cygnus with bright Deneb are visible in the West, and so is the bright star Vega. Furthermore, one can find the Andromeda Galaxy as follows: getting away from town lights and using binoculars, look at second base of Pegasus’s Great Square, then go straight up about 10 degrees (the width of a fist at arm’s length) and look for a small smudge in the binoculars. That’s the Andromeda Nebula, our closest galactic neighbor at 2.5 million lightyears, hosting approximately 1 trillion stars and being a spiral galaxy, in other words it’s really similar to our own Milky Way.
In the East find Leo with bright Regulus and a bright intruder, the planet Saturn. And finally, watching a big finale in the South, find the great constellations of winter centered on Orion with its brightest stars, red Betelgeuse and blue Rigel, its belt and sword containing the Orion nebula, a star forming region and also a great target for binoculars; to its lower left lies Canis Major with the sky’s brightest star Sirius – Venus and Jupiter are brighter but they’re planets; to its left the star Procyon in its imperceptible constellation Canis Minor; to its upper left Gemini with its stars Castor and Pollux; above it Auriga in the shape of a pentagon with Capella; and to its upper right Taurus with red Aldebaran in the arrow head shaped open cluster Hyades and the most prominent open cluster Pleiades. When it gets cold and clear, bundle up, have cookies and hot chocolate at hand, and brave the cold to marvel at the best views the Northern hemisphere is offering. Also, if you happen to use hot rum to stay warm, invite me too.
I have to admit that Comet McNaught caught me off guard early last month. However, it was so close to the Sun that it was tough to find anyway, so unfortunately we didn’t miss out on much by not knowing about the comet. In the meantime it had become spectacular in the Southern hemisphere: check out great images from Chile, South Africa, New Zealand, Australia and other locales in the Indian Ocean on spaceweather.com.
A couple of beautiful sights are the open clusters in Taurus, the Pleiades and the Hyades. The Pleiades, also called the Seven Sisters, appear as a mini dipper at a distance of 440 lightyears, containing about 500 stars and having evolved from a stellar nebula only about 100 million years ago. An open cluster orbits within our galaxy’s disk and its gravitational interaction with other stars will eventually disperse its stars; a globular cluster – there are some in Gemini and Auriga that can be seen with binoculars – in contrast orbits our galaxy at steep angles at distances of thousands of lightyears, its typically 100,000 stars stay gravitionally locked together, and they were born billions of years ago (both types of star clusters are ideal examples for stellar evolution with one of the main astrophysical tools, the Hertzsprung-Russell diagram, supplying their age). The Hyades are the clostest open cluster at 151 lightyears from our solar system with 100 stars and an age of 700 billion years. Open clusters are used for measuring accurate distances as well by recording its stars’s proper motion as they are moving towards a common vanishing point (a method also used in the arts for perspective drawings). However, even closer is the Ursa Major Moving Group at only 80 lightyears. While one characteristic of open and globular clusters is their stars’s proximity to each other, the UMa Group is really spread out with 5 of the Big Dipper’s stars moving in the same direction.
I’ll be offering a couple of free community classes on February 19 and 26 at 7 pm at KPC, probably covering observation techniques and doing outside observations.
The Sky in January 2007
The view is toward
Southeast between 7 pm and 10 pm throughout January; because of Earth’s
rotation, this part of the sky moves through the South into the Southwest each
night all night long. Three constellations are dominating the sky: Orion
the hunter, Gemini the twins, and Taurus the bull. This part of the sky is probably the most
interesting and brilliant since it contains a number of easily seen deep sky
objects as well as eight of the twenty brightest stars. Starting with Sirius,
the brightest one of all, on the horizon, we go clockwise to Procyon, then the
twin stars Castor and Pollux, then yellow Capella (just outside the diagram on
top left), then red Aldebaran in Taurus’ arrowhead, and finally close the
circle with blue Rigel and red Betelgeuse in Orion.
What makes a star (or any other object, e.g. a planet or our Moon) appear bright or faint depends on how bright the star really is and how close it is. Sirius and Procyon are actually the least luminous of these stars but are the closest at 9 and 11 light years. In contrast, Betelgeuse is at a distance of 430 ly but almost makes up for it by being 400 times brighter than Sirius.
Rigel, a blue supergiant at Orion’s foot, and Capella, a yellow normal giant high above Gemini, make for a good comparison. As they are of virtually the same apparent brightness, Capella is 42 ly close while Rigel is 770 ly far, i.e. 18 times further. But the latter is also 315 times more luminous; doing the math and knowing that brightness diminishes with the square of distance, 18^2 = 324, they appear virtually equally bright as seen from our solar system. Their difference in luminosity is originally based on their mass, 2.7 solar masses for Capella and 17 solar masses for Rigel. For a star to be in a balance between gravitation (due to its mass) and gas pressure (due to its high internal temperature), it has to be of a certain size and surface temperature: Capella has a diameter of 9 million miles (ten times that of our Sun) and a surface temperature of 10,000 F (making it yellow; virtually the same as our Sun) while Rigel has a diameter of 61 million miles (roughly the orbit of Mercury) and a surface temperature of 20,000 F (making it blue). Those two properties explain why Rigel is so much more luminous than Capella.
Aside from stars, there is of course the Orion nebula, a birth place for stars, making up the sword which can be glimpsed with binoculars. We find two prominent star clusters in Taurus, the Pleiades (just outside the diagram on top right) and the Hyades (the arrowhead surrounding Aldebaran) which can easily be seen with the naked eye. Stretching from Gemini up to Capella are four star clusters which need some prodding when using binoculars. Since Gemini and Taurus are also Zodiac constellations, planets regularly move through them, as Mars will do next winter.
Other prominent constellations and stars in the sky are the Little Dipper high in the North, the Big Dipper in the Northeast, Cassiopeia’s W almost in the Zenith (overhead), Pegasus’s Great Square low in the West, and Cygnus’s cross with bright Deneb and next to it bright Vega, both low in the Northwest.
As for planets, Saturn rises between 8 pm and 10 pm due East, together with bright Regulus in Leo. Jupiter can be seen very, very low in the South around 8 am. Mars, Mercury and Neptune are within our Sun’s glare during dusk and dawn. Venus should become visible just after sunset low in the Southwest (“Neptune lies close by on January 19th and is just visible in 10x50 binoculars. The light skies will not help but with Venus nearby you may just have a chance at spotting it.” quoted from http://www.astrospace.co.uk/nightsky/MonthlyNightSky.htm). Uranus is potentially visible after dusk but it’s best to check online for finder charts (e.g. on the above web site).
Good sources for sky maps are Astronomy and Sky & Telescope magazines, available at Freddies and Safeway, and online monthly sky charts at skymaps.com and at skytonight.com.
The Sky in December 2006
Last month’s Mercury transit
was a great success, owing mostly to clear skies and it happening in the middle
of an Alaskan winter day. About 100 people showed up to look through my
telescopes and at projected images of our Sun, showing a beautiful sunspot and
of course the transiting Mercury moving across our Sun’s surface. Thanks
also go to my students who helped set up - specifically Mike Stacy - and to
Scott Moon who shot and published a nice transit photo. Enough self-accolades.
The chart shows the evening sky during December – 8 pm early and 6 pm late in the month. Stars with an asterisk * attached are marked as dots in the chart.
Still high in the sky is the “summer” triangle, made up of Lyra’s Vega*, Cygnus’ Deneb* - a long necked swan, shown as the northern cross on the chart - and Aquila’s Altair*. From South to North several prominent constellations, the great square of Pegasus, also appearing as a baseball diamond with Markab at home base and Scheat, Alpheratz and Algenib on first, second and third base, the W of Cassiopeia with its brighter stars Schedar and Caph, the fainter house of Cepheus, the little and big dippers of Ursa Minor and Major – the small and large bears – and the bear watcher Bootes which is setting in the North. Ursa Minor’s brighter stars are Polaris which is within 1 degree of the North celestial pole and Kochab. Ursa Major’s prominent stars are Merak and Dubhe in its dipper which are also the pointer stars for Polaris. Polaris derives its fame of course from being the pole star and therefore very important for navigation; a common mistake is to assume that it appears very bright while in fact there are 48 brighter stars seen in the sky. Also in Ursa Major is the double star Mizar and Alcor in the bend of the handle.
Orion, the Hunter, is about to rise. It is many people’s favorite because of its brilliance. Four stars arranged in a rectangle - red Betelgeuse*, blue Rigel*, Bellatrix, and Saiph - outline the body, while three stars make up the belt - Alnitak, Alinalam, Mintaka - with the Orion nebula as the sword beneath it. Above Orion you find Taurus, part of it in the shape of an arrowhead including red Aldebaran*. And above that are the Pleiades* or Seven Sisters, a must for binoculars. To Taurus’ left is the pentagon Auriga with yellow Capella*. Beneath Capella appear Castor* and Pollux*, the twins in Gemini. And then we close this circle towards the horizon, with Procyon and the Number One: Sirius, the brightest star in the entire sky; both of which will rise about two to three hours after Orion.
Along with them the only night planet this winter will rise. Around midnight notice two bright objects standing above the Eastern horizon. The lower one is Regulus, the brightest star in Leo, the Lion, a constellation easily recognized as such. The other object is our solar system’s gem, Saturn. In high-powered and stabilized binoculars or in low-power telescopes one can get a hint at its rings and see its brightest moon Titan too.
For early risers, watch Orion setting in the West just before dawn. Now Regulus and Saturn appear high in the South.
Around December 14, the Geminid meteor shower will be at maximum with up to 75 meteors per hour. However, light from the waning Moon will interfere. Still, at that rate it may any year’s best meteor shower, even outdoing the Perseids in August which battle the all too bright Alaskan summer nights anyway. While almost all meteor showers are associated with debris from comets, the Geminids derive from the asteroid Phaeton’s jetsam.
Later in the month Jupiter can be glanced very low in the southeast just before dawn. Mars and Mercury would join the giant planet too but they’re rising too late in Alaskan skies.
The Sky in November 2006
The most exciting astronomical event this month is the Mercury transit on
Wednesday, November 8, from 10 am to 3 pm. I will have telescopes set up on the
KPC front lawn, equipped with proper solar filters. Only the two inner planets,
Mercury and Venus, can get between us and our Sun. Because their orbits
are tilted - and despite the fact that they only need 88 days and 225 days,
respectively - such so-called transits are rare (because usually they orbit too
high or too low): at least Mercury transits every seven years on the average
but Venus only twice every 130 years or so. I was able to see a Venus
transit soon in June 2004 from Barrow and plan on the 2012 one seen from Alaska
as well. In the meantime Mercury transits once more (after the recent 99
and 03) which can be seen at least partially (during sunset or sunrise) from all
of the Americas, East Asia, Indonesia and Australia and all of it from Alaska,
the Western US and Canada, and Hawaii. Mercury will appear as a tiny disk
against our Sun's huge disk. Photos of the last Mercury transits in
November 1999 and May 2003 can be seen at my web page
http://chinook.kpc.alaska.edu/~ifafv/ by clicking on my planet lecture.
People stopping by at my telescopes (equipped with proper solar filters) are
usually amazed by how huge our Sun is compared to a planet (Earth wouldn't
appear much bigger). This is Mercury's last transit until 2016.
Winter has almost arrived and that means that the bounty of the beautiful
winter sky charmes us once more. The accompanying chart is set for 10 pm in
early evening and midnight in late November (notice also that South is at lower
left), thus more stars will have risen in the earlier evening hours later this
month. Finally Orion, Taurus, Gemini and Auriga are rising in the
East. With them are the bright stars of winter: red Betelgeuse and Aldebaran,
blue Rigel, yellow Capella and next to the twins' Pollux and Castor appears
Saturn, its rings nicely seen in a small telescope. Also included is the
star cluster of the Pleiades, best viewed with binoculars when up to 50 stars
may be seen. Soon the bright stars Procyon and Sirius will follow.
Now in the Zenith are Cassiopeia's W and the House of Cepheus.
Always in the same place is the Little Dipper with Polaris and toward the
Northern horizon appears the Big Dipper. The kite-shaped Bootes is now
setting while the summer triangle consisting of Deneb (the Swan's tail), Vega
and Altair is getting closer to the Western horizon but will be visible until
January since Deneb and Vega are circumpolar in Alaska (they never set).
Apart from watching Mercury during an unusual time - broad daylight - Saturn is
the only planet that can be easily seen this month. It rises in the
Northeast around midnight in early November and around 10 pm late in the
month. High-power, stable binoculars or a telescope are needed to view
its rings.
The Leonids, now a weaker meteor shower, will show during the night of November
17/18.
Our Moon will show us an interesting spectacle. On and around November 7
(plus/minus two days), our Moon will be almost full and will rise at 4:25 pm and
will not set until 2:45 the next day which means our Moon can be seen for 22.5
hours straight. I call this the "Midday Full Moon" as the
winter Moon's answer to summer's Midnight Sun. This can only happen in
Northern latitudes and only in winter. For the same reason that the Sun
can stay up virtually all day when it is in Taurus in late June, the full Moon
appears in Taurus and Gemini and is up just as long. In fact, since its
orbit is tilted by 5 degrees, that pushes the latitude of the midnight sun from
the arctic circle (67 degrees, Coldfoot) to 62 degrees (Talkeetna) and even
further South because atmospheric refraction makes our Moon appear even above
the horizon as seen from the Kenai. The same event repeats in early
December. (See also an article about this by Ralph Hulbert,
http://www.alaskchem.com/moon.htm, in the Anchorage paper two months ago.)
The Sky in October 2006
The stars of fall are back: I highlighted easy to find
constellations such as the Big Dipper, the fainter Little Dipper, kite-shaped
Bootes, W-shaped Cassiopeia, house-like fainter Cepheus, cross-like Cygnus, the
dashed-line Summer Triangle, the Great Square of Pegasus, the arrow-like snout
of Taurus, pentagon-shaped Auriga.
I also highlighted the brightest stars with big dots. Big on star charts
means brighter - no matter how much stars are "magnified" in a
telescope, they're still pinpoints. But they appear brighter and perhaps
their color shows better, indicating the surface temperature of a star, ranging
from 5000 F for "cold" red stars, 11000 F for yellow stars, 20000 F
for white ones up to 40000 F for "hot" blue stars.
There are red Aldebaran in Taurus, yellow Capella in the Northeast, the twins
white Castor and orange Pollux on the northeastern horizon, red Arcturus in
Bootes - the Big Dipper's handle points to this star - and white Deneb, Vega
and Altair which make up the summer triangle; the fainter yellow North star Polaris
is designated by the little cross at the end of the Little Dipper's handle.
To the upper right of Aldebaran, look at the Pleiades or Seven
Sisters. Also of note is Albireo, actually a double star, at the lower
end of the cross with the brighter component showing at a golden yellow in
binoculars and the fainter one being blue.
The arrows show the direction in which the stars seemingly turn around Polaris
- due to Earth rotating in the opposite direction under the stars - with stars
setting in the West and new ones rise in the East.
Aside from these prominent stars and constellations, it's worth noting fainter
and harder to see constellations. Starting from the Southern horizon
going up towards Polaris I'll briefly describe Capricornus, Aquarius, Equuleus,
Delphinus, Lacerta and Cepheus. Capricornus and Aquarius are part of the
Zodiac, i.e. our Sun, our Moon and planets and most asteroids can be found
within these twelve constellations. Right now the planets Neptune and
Uranus can be spooted in Capricornus and Aquarius; on how to find them see my
September column or even better check out skypub.com which has some good finder
charts and features an online interactive star map rather than my static
B&W one. Equuleus means "little horse" and consists mainly
of four dim stars half way between Aquila Pegasus's Great Square . Just
to the left - or better referred to as East - of Aquila 's bright star Altair
lies the equally small Delphinus which obviously means
"dolphin". John Sanford in his "Observing the
Constellations" uses a very nice description: "Delphinus has one of
the most distinctive shapes, that of a slightly flattened diamond with a couple
of fainter stars as a tail." Personally it's one my favorite gems
when I casually look at the heavens without binoculars or a telescope.
Lacerta, the lizard, lies to the upper right - better is northwest - of
Pegasus's Great Square . Look for eight stars making a small zig-zag
line. Cepheus, the king, is a house shaped constellation between the more
prominent Cassiopeia, Cygnus and Ursa Minor. It takes a minute or so to
find the house because Cepheus consists of faint stars and lies on the edge of
our Milky Way which lends a lot of stars to that region.
Although there are no special events this month, mark your calendar for
Wednesday, November 8, when Mercury will transit our Sun. I will announce
a public viewing for that.
The Sky in September 2006
Planets:
A very bright Jupiter can be seen very low in the Southwest just after
sunset. And a very bright Venus is visible very low in the East just
before sunrise.
Better situated is Saturn: it’s best seen by commuters along the
September provides also the best chance to see the faint planets Uranus and
Neptune, hence the supplied charts of Aquarius and Capricorn. On a very
clear night without haze, you need to look very low on the Southern horizon
(best is at the
Stars: To first orientate yourself first, find the Big Dipper low in the Northwest; then extend the dipper's last two stars high into the North to find Polaris, the North Star, and the Little Dipper; with the Big Dipper on one side of Polaris, find the constellation Cassiopeia, a nicely shaped W, on the other side of Polaris high in the Northeast. Back to the Big Dipper, follow the curve of its handle toward the bright Red Giant Arcturus low in the West with its constellation of Bootes above, appearing as a kite or cone shape. Notice the bowl shaped Corona Borealis to its upper left. Prominently high overhead and extending to the South is the Summer Triangle, made up of the three bright stars Vega, Deneb and Altair. Deneb's constellation of Cygnus, the Swan, in a cross shape is easily seen; Vega's small rectangular shaped Lyra, the Harp, is prominent as well; while Altair's Aquila or Eagle may be depicted by its wings. But just on the upper left of Altair is the dolphin shaped small constellation Delphinus. Also prominent in the Southeast are the Great Square of Pegasus and low in the Northeast bright yellowish Capella with its pentagon shaped constellation Auriga. By morning, constellations have rotated towards the West with some of them having set while other have risen in the East. Those are Orion, Taurus, Gemini, Cancer and Leo as well as the planets described above.
Have fun observing, I'm looking forward to hopefully clear skies this winter and the Astronomy class I'll be teaching this fall.
Pluto: This is the IAU’s official definition on planets and other objects orbiting our Sun, with 237 yeah votes and 157 nay votes, 60% vs. 40%, among 424 astronomers present at the time of voting on August 24, 2006, at the meeting of the International Astronomical Union in Prague, Czech Republic, out of 2411 registered at the conference (the vote took place on the last day of the conference, hence rather few people voted), out of a few tens of thousands professional astronomers and millions of amateur astronomers world-wide:
(1) A "planet" [1] is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
(2) A "dwarf planet" is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape [2], (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
(3) All other objects [3] except satellites orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".
Footnotes:
[1] The eight planets are: Mercury, Venus,
Earth,
Mars,
Jupiter, Saturn,
Uranus, and Neptune.
[2] An IAU process will be established to assign borderline objects into either
"dwarf planet" and other categories.
[3] These currently include most of the Solar System asteroids, most
Trans-Neptunian Objects (TNOs), comets, and other small bodies.
The IAU further resolves:
Pluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.
Astronomers seem to be divided about the decision as well as about Pluto’s status. As Pluto had been designated a planet for 75 years, in my opinion, the decision by the IAU to demote it to dwarf planet status is too new and the vote too contentious that the last word has not been spoken about it. So for at least the near future I go along with my preference which is that I continue labeling it as a planet. There’s not really a rationale behind it why I prefer Pluto being a planet – other than its long status as such – but perhaps with time I may change my opinion.
On a final note one may ask why there should be such a vote and if scientists can actually vote on scientific aspects. The answer to the first question is that there had not been an official definition of what a planet is, only the historical notion that planets are “wanderers” among the stars on the celestial sphere. The answer to the second question is that scientists are prohibited from voting on scientific issues because it’s nature and the evidence it reveals that determines scientific conclusions. However, voting on a definition is not about science: a definition of what a planet is is merely meant to categorize objects; hence the vote at the IAU conference is completely legitimate (as is the non-acceptance of individualized star names). In a similar vein, the taxa (kingdom, phylum etc.) used in biology simply categorize organisms and these definitions are agreed upon by biologists; on the other hand, all scientific conclusions in biology are based on data that nature provides, not biologists’ opinions or votes.
A few years ago astronomers voted that based on the data, the universe is not only expanding but that its expansion is even accelerating. Now that is a scientific conclusion (based on the data) for which a vote – even among respected astronomers – is meaningless.
Not needed:
Zodiac:
From August 10 through September 16 our Sun has been traveling through Leo and until October 30 it will be in Virgo. The astronomical path is different from astrology (Virgo and Libra in September) because the tilt of the Earth’s axis is continuously changing (precession) and hence our Sun is about one Zodiac constellation behind from where it was 4000 years ago when the signs became stylish. However, since our Sun is inside these constellations, they’re not visible anyway right now. More interesting is a constellation that’s exactly opposite Leo which is Aquarius.
This is probably the best month to see Aquarius, visible about half a year away from its assigned time (February). Best time to find it is on September 6 and 7 when the full Moon resides in that constellation. Between dusk and dawn find our Moon low on the southern horizon.
Eclipses:
Two eclipses occur this month but
neither of them is visible from
The next lunar eclipse viewed from
The Sky in April 2006
Days are getting longer and nights are getting shorter. We're also
leaving the freezing cold behind. As we all love winter's benefits, we
surely regret that our beloved starry skies will take a back seat soon.
But at least we get some nice views for a good-bye.
With Daylight Savings Time having started, it doesn't get dark until 10
pm or even later and therefore the diagram shows the Southeastern sky around 11
pm with very bright Jupiter making up a beautiful isosceles triangle with the
bright stars Arcturus and Spica, which they will continue to depict throughout
spring of this year. For the diagram itself I chose April 13 because the
full Moon appears between Spica and Jupiter; the day before it's next to Spica,
the day after next to Jupiter, showing nicely our Moon's West-to-East motion as
it's orbiting us.
I'm alternating between two planetarium software, Redshft 3
and Starry Night Pro, to draw my diagrams: since SNP shows landmarks on the
horizon, I chose it and as I was running it, I noticed that there are quite a
few bright satellites orbiting through this part of the sky. One
distinguishes satellites from airplanes since the former' paths of flight are
very linear and stable, seem very high up and brighten up, then fade; that's due
to them reflecting our Sun's light, which is beneath the Western horizon
at this time, more or less efficiently, in fact, the satellites fade as they
enter Earth's shadow in the East or are rather backlit in the West. The
best web site to check for satellite fly-bys is www.heavens-above.com (Chris
Peat in Germany maintains it), start out by entering your exact location,
respectively access its location database which includes towns as small as
Kasilof and Tyonek.
Saturn is still visible: you find it as it makes a very
obtuse triangle with Gemini's Castor and Pollux low in the West. The
pretty Beehive cluster (great in binoculars) is just to the left of Saturn and
can be seen with the naked eye, as I noticed even in locations where some
streetlights are diminishing the view. In a small telescope Saturn's
rings can be spotted, some of its moons, especially Titan, and Jupiter's four
large moons as well.
Mars is rapidly moving from Taurus into Gemini, during April
it can be seen above Orion on the Western horizon, however rather early during
dusk. With it the winter sky with its brilliant stars and constellations,
Sirius, Procyon, Aldebaran, Castor, Pollux, Capella, Betelgeuse, Rigel, Orion,
Taurus, Gemini, and Auriga, is giving its last hooray for the season until we
meet them again in November, to which, I'm positive, we're all looking forward
to.
Venus and Mercury appear so low during dawn in Alaskan skies
that it may be better to look at them during a trip to the second-largest state
in the US.
The Sky in March 2006
Since the winter sky appears now in all its splendor, I just show the most
interesting and most beautiful part of it, all those bright stars in the South;
instead of the entire sky as I usually do. There is the hunter Orion with
its belt and sword and the bright stars Betelgeuse and Rigel. By
themselves are Sirius and Procyon in the Big Dog and the Little Dog,
respectively, forming a nice straight line with Saturn which itself is just to
the right of the Beehive cluster. The twins, Gemini, are marked by Castor
and Pollux. The pentagon of the charioteer Auriga with bright star
Capella appears highest. And the bull Taurus with Aldebaran and the
cluster of the Pleiades hosts Mars. Enjoy.
The planets: aside from the just mentioned Mars and Saturn,
around midnight Jupiter rises in the East and becomes prominent in the low
Southeastern sky during the rest of the night; Venus rises just ahead of our
Sun but it's so low in the sky that one has to scan the Southeastern horizon
carefully during dawn.
A total solar eclipse will visit Northern Africa, Turkey and
Central Asia on March 29; Europe and the rest of Africa and most of Asia will
see a partial eclipse. Because of it accessibility it finds mention here:
every few years a prominent eclipse can be seen somewhere in the world, '91 in
Hawaii and Mexico, '99 in Europe, '06 in Northern Africa, '09 in China;
although there are two solar eclipses every year, many of them are only partial
ones and many are in inaccessible places (e.g. '08 in Antarctica). A
solar eclipse is accompanied by a lunar eclipse, in this case two weeks prior,
on March 14, on the same continents of Africa, Europe and Asia.
A friend of mine told me of an office discussion she had:
are winter days and nights in Barrow completely dark or does our Moon supply
some light? I haven't been in Barrow in the winter (I'm still failing to
convince my wife of this opportunity), so I can't answer that first hand.
But some astronomical knowledge does supply the answer. For one,
since our Sun is closer beneath, but not above, the Southern horizon during
mid-day, I imagine that the sky looks like dawn and dusk for a few hours.
And then there's our Moon perhaps in the sky, depending on its position
in its orbit. Both Sun and Moon as well as planets and asteroids move
along or at least very close to a path called the ecliptic, a circle that
stretches across the sky through the Zodiac constellations. (Moon,
planets and asteroids do that while in the case of our Sun it's actually us,
Earth, which is orbiting; but from our vantage point it seems that our Sun is
the orbiting body. And that's the necessary vantage point used in this
discussion.) Our Sun sweeps through these constellations once per year,
i.e. relatively slowly. Since Taurus, Gemini and Cancer are Zodiac
constellations that appear quite high in the sky (in the Northern hemisphere)
and our Sun moves through them between May and August and becomes circumpolar
(meaning that it never sets), that's when we have summer. And since
Scorpius, Sagittarius and Capricornus are really low in the sky (in fact,
they're for the most part not even visible from Barrow) and that's where our
Sun is from November to February and therefore barely rises above the horizon,
we have winter at that time. Our Moon on the other hand moves through
these constellations once a month, i.e. relatively fast. So once per
month, every month, it's very high in the sky and circumpolar in Barrow for a
few days; and every month it's below the horizon all day (and night) long for a
few days. For example, during most of December our Sun is in Scorpius and
thus never rises. But when our Moon is in Taurus, as it was in
mid-December, it itself is circumpolar and very high in the sky. Since
Taurus is in the opposite part of the sky from Scorpius, our Moon was also full
at that time: Barrow must have had beautiful circumpolar full Moon nights and
"days" during mid-months this past winter.
The Sky in February 2006
I, the Sky Guy, the Great Astronomer, have to admit that I
have not used my telescope in more than a month. Between school starting,
the many cloudy evenings, the hassle of assembling the telescope in a cramped
garage versus keeping it safe from our 1 year old son, and our sub-zero
temperatures, it just wasn't feasible. I'll get better at it though as I
have scheduled some astronomy evenings for one of my classes during February.
If you like to join, send me an e-mail or call me.
The evening sky has changed so little from January that I
actually recycle the diagram from last month (Mars has shifted a bit towards
the Pleiades). I outlined the following constellations that should be
easy to find because they're highly recognizable: the Big Dipper high in the
Northeast, Orion in the South, Auriga (a Pentagon) high in the South, the
Square of Pegasus in the West, the Cross of Cygnus in the Northwest;
furthermore, these take a moment to find: the lion Leo in the East, the Snout
of Taurus the Bull (also in the shape of an arrowhead) above Orion, the Little
Dipper high in the North (use the pointer stars in the Big Dipper to find
Polaris), the W of Cassiopeia on the Western side of the Little Dipper,
opposite from the Big Dipper.
The labeled stars are the brightest ones in the winter sky;
I'm labeling them beginning in the middle, then spiraling counterclockwise:
Capella (6th), Castor (45th), Pollux (16th), Beehive cluster, Saturn
(a planet), Regulus (21st), Procyon (8th), Sirius (1st), Betelgeuse (10th), Rigel
(7th), Aldebaran (13th), Pleiades (another cluster), Mars
(another planet), Deneb (19th), Vega (5th), and Arcturus (3rd). There are
some stars in the Big Dipper and in Orion that are brighter than Polaris (49th)
but obviously Polaris seems more important. See if your observations of
the brightest stars match the offical list as I cited it; if not, think about
what could make them appear different to your eyes; and see how the planets fit
into this brighness scale.
Still long after midnight, Arcturus will be joined by Spica
(15th) and Jupiter, resembling a beautiful right triangle in the Eastern sky.
Despite its wee hours appearance we need to enjoy Jupiter now because it
will shine at its best in summer when we hardly get dark skies. Then
again, perhaps Jupiter will be the only bright object we can see in June and
July.
This month I like to talk about the constellation Leo.
Among the 88 constellations it also belongs to the few that can be
recognized easily as what it should depict, i.e. a male lion lying down with
his tail behind him and a faint mane above his body. The bright star
Regulus is his front paw. I consider Leo a quick constellation in the
sense that it can be seen for an only relatively short time in the evening sky,
from January to April. Of course it "moves" just as fast as the
other constellations but, as we're getting out of winter into spring, our
evenings get shorter as our Sun rises later. Thus Leo isn't in the
evening sky for very long and hence I also regard it as a messenger for spring
to arrive (imagine that).
Leo is also a prime example for explaining the meanning of
the Zodiac constellations. People born July or August have the sign
of Leo (I'm not expounding on Astrology but that's the only overlap this
quackery has with the science of Astronomy). During those months, a
Zodiac constellation can't be seen because by definition that's where our Sun
is. Instead we can observe it half a year removed. E.g. I have to
wait to see my constellation of Aquarius until early fall.
Next month I'll talk about the total solar eclipse that will
be visible in Northern Africa, Turkey and Western Asia. I may not be of
concern to us here in Alaska but perhaps somebody is making travel plans.
At some point even I thought about flying to Istanbul.
The Sky in January 2006
I don't know if people in other professions do this and I don't know about
other teachers, but I'm of the sort who constantly thinks about how I can use a
particular situation or event in the classroom. For instance, while
driving (and paying attention), I think about all the physics that's involved
that makes the car move and how I can use that in class. Or I may kayak
for leisure (in the summer) and make up lesson plans in my head. It's
quite bothersome.
When I moved here a few years ago, I knew that I'm just about 7 degrees too far
South to see the Midnight Sun but it crossed my mind that due to our Moon's
inclined orbit (by 5 degrees) we could actually almost see a Noon Full Moon.
I made that term up. It's quite bothersome. I think back then
I even figured out when that should happen: December 2005. Well, I spaced
that. If you noticed the full moon very high in the evening sky last
month, it wasn't because you read my column. So my little story is just
about saying sorry.
But why write about events past if they repeat? I'm looking forward to
December 2006 when this happens again and the full Moon will be 58 degrees
above the horizon around midnight and will rise barely East of North and set
barely West of North, both occurring around noon. Enough for now, I will
bring this up in my next December column.
But back to this month: our Moon does have an interesting event in store for us
as it will occult the Pleiades cluster during the night of January 9/10, Monday
to Tuesday. On Sunday, the 8th, or before that day, check on the Pleiades
in Taurus and notice that our Moon is closing in on it (passing by Mars in the
process). On Monday, you may notice the almost full moon very low in the
East even before sunset. After nightfall, around 6 pm, notice that there
are no Pleiades. Then follow our Moon through the night and glimpse the
Pleaides again, emerging on the right side of our Moon (its East side but our
Western direction) shortly before midnight. By the way, the effect of an
occultation is the same as that of an eclipse, as we don't see the occulted
object; the difference is that no shadows are involved.
Venus retreats from the evening sky in January, it hasn't been a great Venus
apparition anyway. But we will enjoy it as a morning planet throughout
the entire spring. Whenever you make an early trip to Acnchorage,
starting just before dawn and driving East on the Sterling Highway, you'll see
Venus above the Kenai Mountains. Mars appears in the South about 45
degrees in the evening, just West of the Pleiades. Saturn follows suit,
rising around sunset. Since it's still near so many bright stars, it's a
little tougher to spot, although it's brightest this month since it reaches
opposition when it's closest to us on January 27. Try to find the twins,
Castor and Pollux, and to their left (further East) is the ringed planet.
Jupiter still rises in the wee hours. Find it low in the South,
being by far the brightest member of a rectangular triangle containing also the
bright stars Arcturus and Spica.
The chart shows the sky around midnight in early January and around 10 pm in
late January. Highlighted constellations in the North are Cygnus, the
Swan or Northern Cross, and the stars Deneb and Vega (notice the first letters
used); in the Northeast the star Arcturus (the Big Dipper's handle curves
toward it); in the West the Great Square of Pegasus; overhead the Big Dipper,
the Little Dipper with Polaris, and the W of Cassiopeia; and in the South the
glorious winter sky with the constellations Orion, the pentagon of Auriga, the
snout of the bull Taurus (looks also like an arrowhead) and Gemini, the twins,
with the bright stars, listed counterclockwise, Betelgeuse, Rigel, Aldebaran,
Capella, Castor, Pollux, Regulus, Procyon and Sirius with Mars and Saturn
flanking them. Also highlighted are the star clusters of the Pleiades and
Beehive, the latter is found with binoculars as it lies just to the upper right
of Saturn.
Last month I described Auriga, this month I like to cover Orion, the Hunter,
that most famous of constellations. Mostly it's famous for being so
easily recognizable and made up of so many bright stars. There are
Betelgeuse (right shoulder) and Rigel (left foot), one a Super-Red-Giant, the
other a Blue Giant. Even the untrained human eye should easily see the
non-white color of a small number of stars: our yellow Sun, the Red Giant stars
Aldebaran, Antares, Arcturus, Betelegeuse, and the blue Giant Rigel. The
other prominent five stars in Orion are also blue but it only shows in
telescopes, which collect more light and therefore enhance color. Those
are Bellatrix (left shoulder), Saiph (right foot), and Alnitak, Alnilam and
Mintaka which make up the belt (in East to West order). There is also the
Orion nebula, just visible with binoculars. In a good amateur telescope,
the trapezium of very hot, blue, and young stars can be glimpsed, those progenitors
of all the stars that are about and will be born in this stellar nursery.
Just South of Alnitak lies a bright nebula (the term meaning "it
looks like haze") against which a dark nebula is silhouetted in the form
of the Horsehead Nebula, also a sight for large amateur telescopes.
As an afterthought, we're closest to our Sun on January 4, at 91, 405,953 miles
(the perihelion), exactly 3,101,962 miles closer than on July 3 (the aphelion).
And on Thursday, Janaury 5, I'll have my telescopes pointed at some of
the marvels described above, starting around 5:30 pm, on the KPC parking lot
during our Open House and walk-in registration.
The Sky in December 2005
The
dominating constellation is Orion, the Hunter. It is many people’s
favorite because of its brilliance. Four stars arranged in a rectangle
(with red Betelgeuse, blue Rigel, Bellatrix, and Saiph) outline the body, while
three stars make up the belt with the Orion nebula as the sword beneath
it. Above Orion you find Taurus, part of it in the shape of an arrowhead
including red ALDEBARAN. And above that are the Pleiades or Seven
Sisters, a must for binoculars. To Taurus’ left is the pentagon
Auriga with yellow CAPELLA. Beneath Capella appear CASTOR and POLLUX, the
twins in Gemini. And then we close this circle towards the horizon, with
Procyon and the Number One: Sirius, the brightest star in the entire sky.
Since Jupiter resides further East , also look for Cancer and Leo.
If you're wondering why some of the above constellations don't show in the
diagram, you're right: above I described the late evening sky and since I trust
that you'll be able to find Orion, I opted to show the early evening sky
instead so that you can locate one very bright object, that is planet.
See the text below.
However, there is more in the sky: the huge summer triangle is called that way
because it’s the dominant feature in the summer sky but is still visible
until January in the West. It is comprised of VEGA, DENEB and ALTAIR,
another three of the brightest stars. Since these three stars are from
different constellations (Lyra, Cygnus,
If you happen to be in a dark area, even a turn-out on the
How do you find the North star Polaris? Take the last two stars of the
Big Dipper’s pan and mark off a distance five times their separation,
towards North. You’ll always end up at Polaris which is the last
star of the smaller and fainter Little Dipper. Since the Little
Dipper’s stars are fainter, you might need to be in a darker area without
light pollution. You can also depict the two dippers as if you were
flipping pancakes forth and back between the two. Polaris is only 49th in
brightness and thus appears way fainter then most people expect: its claim to
fame is its fixed position of 60 degrees (marking one’s latitude) above
the Northern horizon, not its brightness.
Venus is by now in the constellation Capricornus but is finally high enough the
SSW horizon that it can be seen as a bright beacon during dusk: look in that
direction, then turn around and see Mars is high in the Eastern sky, some
distance from the Pleiades; it's a nice spectacle. Saturn rises earlier in
the evening and is still following Castor and Pollux. And Jupiter appears
brightly in the Southeast during dawn.
This month I like to mention the constellation Auriga a little more in
depth. It looks like a pentagon and is high in the eastern sky during
evening, placed between Taurus (Aldebaran, Pleiades, and currently Mars) and
Gemini (Castor, Pollux, Saturn). Its brightest star is Capella, its
diameter is 13 times larger than our Sun (12 million miles compared to 900,000
miles), its spectrum is very similar and hence its temperature of 11,000 F as
well and - it's yellow, a color you may be able to see with binoculars.
Putting these numbers together yields an energy output about 160 times as
much as our Sun's but of course at its distance of 45 lightyears, only some of
its light reaches us, making it the sixth brightest star in appearance from our
solar system (Sun excluded). Auriga lies also inside the Milky Way, so
you see more (fainter) stars looking at it while for example looking at the Big
Dipper. Not coincidentally it also bears some open clusters as these
conglomerates of several hundreds of stars each were formed within our galactic
disk. These have the prosaic names M37, M36, and M38. All are
towards the lower left corner of the pentagon (the opposite side from Capella)
and while each at magnitudes 5.5 to 6.5 are just on the brink of naked eye
visibility, all three are fine objects for binoculars. M37 contains about
150 stars within a diameter of 25 ly and at a distance of 4600 ly; M36 has only
60 stars within 14 ly and at 4100 ly from us; and M38 has about 100 stars
within 25 ly and at 4200 ly from us. Since all three are at roughly the
same distance from us, they all appear almost equally bright.
Last but not least, my community schools Astronomy class has its last evening
on Wednesda, December 14 at KPC.
The Sky in November 2005
Winter
has almost arrived and that means that the bounty of the beautiful winter sky
charms us once more. The accompanying chart is set for 10pm in early evening
and midnight in late November, thus more stars will have risen in the earlier
evening hours later this month. Finally Orion, Taurus, Gemini and Auriga
are rising in the East. Inside these constellations are the bright stars
of winter: red Betelgeuse and Aldebaran, blue Rigel , yellow Capella and next
to the twins' Pollux and Castor appears Saturn, its rings nicely seen in a
small telescope. Also included is the star cluster of the Pleiades, best
viewed with binoculars when up to 50 stars may be seen. Soon the bright
stars Procyon and Sirius will follow. Now in the Zenith are Cassiopeia's
W and the House of Cepehus.
Always in the same place is the Little Dipper with Polaris and toward the
Northern horizon appears the Big Dipper. The kite-shaped Bootes is now
setting while the summer triangle consisting of Deneb (the Swan's tail), Vega
and Altair is getting closer to the Western horizon but will be visible well
into January since Deneb and Vega are circumpolar in Alaska (they never set).
Mercury and Venus are visible during dusk; however, they’re very low in
the sky this month since they’re in the constellations of Scorpius and
Sagittarius, respectively, and those two are very low constellations as seen
from Alaska. Look for Venus during dusk near the Southwestern horizon;
starting on November 5, the crescent moon may help point to Venus.
Mars rises around sunset, though of course in the East. It is followed by
the star cluster Pleiades and red Aldebaran, both in Taurus; look for an
elongated triangle made up of these three objects. Mars is in opposition
this month which means it’s closest to us. You might be able to see
a disk in binoculars but definitely use them for marveling at the stars in the
Pleiades. By mid-November, the full moon has joined Mars.
Once Taurus is up and after Gemini has risen by late evening, around midnight
perhaps, look for Saturn following suit in Cancer. Again use binoculars
(probably without hope for seeing the rings; a small telescope would be needed)
but scan just a little ahead from Saturn to look at another pretty star
cluster, the Beehive in Cancer. A gibbous moon will accompany Saturn
around November 21.
Jupiter rises shortly before dawn in the Southeast. And since Alaska
nights get longer every day, you’ll see it during your morning commutes,
if you happen to drive East. The crescent moon, this time the waning one,
will be near Jupiter at the end of the month.
Also, my community school class starts on Wednesday, November 9 (instead of
11-02), at KPC around 7:15 pm. If it’s clear, we’ll
definitely be outside observing. Around that time our Moon will be full
and since that compromises views of the starry skies anyway, I prefer a more
convenient viewing area such as KPC’s gravel pit across from our parking
lot.
The Sky in October 2005
The stars of fall are back: this time I highlighted easy to find constellations
such as the Big Dipper, the fainter Little Dipper, kite-shaped Bootes, W-shaped
Cassiopeia, house-like fainter Cepheus, cross-like Cygnus, the Summer Triangle
(dashed line), the Great Square of Pegasus, the arrow-like snout of Taurus,
pentagon-shaped Auriga. I also just highlighted the brightest stars (though
I abstained from naming them on the chart, fearing information overload), red
Aldebaran in Taurus, yellow Capella in the Northeast, the twins Castor and
Pollux on the NE horizon, red Arcturus in Bootes (the Big Dipper's handle
points to this star), and Deneb, Vega and Altair that make up the summer
triangle; the fainter North star Polaris is designated by the little cross at
the end of the Little Dipper's handle. To the upper right of Aldebaran,
look at the Peiades or Seven Sisters while Mars completes the views in
Taurus. The arrows show the direction in which the stars seemingly turn
because of Earth rotating in the opposite direction under the stars. That
means that stars set in the West and new ones rise in the East during the night,
including the planet Saturn which will show itself around 2 am.
On Monday, October 17, a partial lunar eclipse will be visible from 3:30 am to
4:30 am in Alaska, relatively high in the Southwest. However, it's a
faint one since our Moon barely grazes Earth's shadow.
Good sources for information are as always the two major magazines in the US,
Sky & Telescope and Astronomy, available in many stores that carry large
magazine collections and at many libraries. The charts and descriptions
found in these magazines are for the most part applicable in Alaska too but
since they're wittern for the Lower 48, there are differences between the
latitudes. Though we are further West, we also have our own time zone, so
times of ordinary, recurring celestial events are the same; hence longitude
doesn't matter as far as the usefulness of charts is concerned. In the
East-West direction, only special events would have to be corrected for: for
example, the solar eclipse on October 3 peaks - and is published as such - at
10:32 UT (Greenwich time), converted that gives 2:32 am ADT, right in the
middle of night when our Sun is inconveniently beneath the horizon; on ther
other hand, the partial lunar eclipse is scheduled for October 17 with its peak
at 12:03 UT which makes that 4:03 am, again during the night but of course it's
the full moon, so that timing is appreciated.
Now latitude is a diiferent story. In Southcentral Alaska we're at 60
degrees, compared to Portland's 45 and Denver's 40, to give a couple examples.
From that results that the entire sky is shifted North to South by about
20 degrees. So when looking at those charts, you need to cover an
appreciable portion of the Southern sky close to the horizon: there are no
Cetus, Piscis Austrinus and virtually no Sagittarius visible from the Kenai and
environs; Capricornus, Aquarius (including Uranus and Neptune), and Pisces are
on the horizon. That's also why people down south were able to enjoy
Jupiter and Venus during dusk while for us they set at the same time as our Sun
(fortunately Venus now starts emerging). On the other hand, Polaris is
shifted toward the middle of the chart, making it appear very high in the sky,
and so is the Big Dipper. In addition, more of the constellations
otherwise beneath the Northern horizon are visible: Auriga (including yellowish
Capella), Lynx, Canes Venatici and especially during winter, the bright stars
Deneb and Vega can be glimpsed.
I also like to advertise the class I'll be teaching for Community Schools
(262-...), starting Wednesday, November 2.
The Sky in September 2005
This would be a good month to watch Venus and Jupiter during dusk but we just
too far north. Both planets and our Sun set virtually at the same time as
seen from Alaska, while, if you're traveling downsouth, you'd see that our Sun
sets first and then the two brightest planets appear nicely visible next to
each each other. Hence I stand slightly corrected from what I mentioned
last month when I indicated that we might see Jupiter from Alaska. Sorry.
Still, Venus will appear in the evening the entire winter long.
Mars in Taurus rises around 10 pm and is visible the entire night. It too
is a winter planet, making a beautiful triangle with the red giant star
Aldebaran and the star cluster Pleiades.
Saturn in Cancer is the dominant object in the pre-dawn skies. With
average binoculars you probably won't see its rings but look right above it and
you see the beautiful Beehive cluster. You can actully see that without
binoculars using averted vision (out of the side of your eye, not directly
looking at it). Saturn's rings are visible with powerful binoculars or a
small telescope.
The chart shows the sky at 3 am throughout September. I used that unusual
time to squeeze Saturn on it. For views earlier during the night and in
the evening, imagine to rotate the chart clockwise, so that stars in the
Northwest, West and Southwest are high in the South, stars beneath the horizon
are in the West (described below) and stars in the Eastern parts have not yet
risen. Still, this doesn't compromise the chart's usefulness.
For the stars themselves: since we are now able to actually see stars in once
again dark environs; this is for the evening sky. To first orientate
yourself first, find the Big Dipper low in the Northwest; then extend the
dipper's last two stars high into the North to find Polaris, the North Star,
and the Little Dipper; with the Big Dipper on one side of Polaris, find the
constellation Cassiopeia, a nicely shaped W, on the other side of Polaris high
in the Northeast. Back to the Big Dipper, follow the curve of its handle
towards the bright Red Giant Arcturus low in the West with its constellation of
Bootes above, appearing as a kite or cone shape. Notice the bowl shaped
Corona Borealis to its upper left. Prominently high overhead and
extending to the South is the Summer Triangle, made up of the three bright
stars Vega, Deneb and Altair. Deneb's constellation of Cygnus, the Swan,
in a cross shape is easily seen; Vega's small rectangular shaped Lyra, the
Harp, is prominent as well; while Altair's Aquila or Eagle may be depicted by
its wings. But just on the upper left of Altair is the dolphin shaped
small constellation Delphinus. Also prominent in the Southeast are the
Great Square of Pegasus and low in the Northeast bright yellowish Capella with
its pentagon shaped constellation Auriga. By morning, constellations have
rotated towards the West with some of them having set while other have risen in
the East. Those are Orion, Taurus, Gemini, Cancer and Leo as well as the
planets described above.
Have fun observing, I'm looking forward to hopefully clear
skies this winter and the Astronomy class I'll be teaching this fall.
The Sky in August 2005
The astronomy season starts out in grandeur as the first major planet will be
Mars at its best. It’ll be joined by Venus and Jupiter early this
fall and Saturn later this year.
The red planet has been an odd-year planet throughout the 90s and 00s, i.e. it
became last prominent in 2003, then now obviously, and next time in late
2007. Mars needs about 1 year and 11 months for one orbit. So as
Earth orbits our Sun and returns to the same spot after exactly one year, Mars
is almost on the other side of our Sun. As we’re trying to catch up
during our second orbit, Mars makes the feeble attempt to elude us, but finally
we’ve caught up and get closest to Mars once again after 2 years and 2
months. Hence the two year recurrence of Mars from our vantage point.
As for late 2005 and early 2006 Mars is moving across Aries from July on until
January where it will also start retrograding in October with our closest
approach on November 6 (Mars' opposition), the on through Taurus in February
and March and through Gemini in April and May of next year.
We like to be close to Mars to observe it because we can only see it when both
of us are on the same side of our Sun, else our Sun would be in between,
rendering Mars obliterated by the bright daytime skies, as will be the case for
the remainder of 2006. But we also like to be closer to a planet because
it appears brighter and bigger, which is especially the case for Mars.
Once again, Mars is in the news for allegedly being closer than ever - quite
forgetting that that happened two years ago. Nevertheless, Mars is a
great sight every other year.
You can’t miss reddish Mars in the East or South, depending on the time
of night , because it’s be the brightest object in the night time sky,
apart from our Moon if that is out . The diagram shows the positions of
Mars during August and September around
There are some bright stars out but none of them is nearly as bright as Mars,
though some of them could be mistaken for Mars. These stars are reddish
Arcturus and Antares in the West and Southwest: these are huge, though cool
[radiating at around 5000 F which corresponds to red] dying stars called Red
Giants, hence unlike Mars which gets its color from its oxidized, rusted
surface rocks. Other bright stars make up the summer triangle overhead, Vega,
Deneb and Altair .
As
every year, August brings the most famous and probably best known meteor show,
visible around August 11-13, Thursday and Friday nights this year. As we
on Earth orbit our Sun, we intercept the orbits of comets (just the orbits, not
the comets themselves, they're in other positions of their orbits) and are
"pelted" by the the debris of these comets that is strewn throughout
their entire orbits: mostly fine dust particles, at best tiny rock pebbles. In
August of each year, we're passing through the orbit of comet Swift-Tuttle and
when we look down its orbit we see the constellation Perseus. Therefore
it appears that the dust particles in Swift-Tuttle's wake are coming from
Perseus and hence the meteor shower is given the name Perseids. These dust
particles then burn up in our atmosphere, creating what's called meteors.
The accompanying diagram shows what you perhaps could see during the
morning hours of August 12. Here you're looking high towards the South.
Try to take photos with a camera that allows time exposures, use a wide
angle lens.
Comets are named after their discoverer(s), in this case independently by
Americans Lewis Swift and Horace Tuttle who noted the comet in 1862; this was
also the first instance that a comet and a meteor shower were shown to be
related phenomena. The comet also goes by the designation 109P, the P
meaning it's a periodic comet that returns in regular intervals, the number
meaning it's one among 164 such comets: designation 1 goes to Halley, 9 to
Tempel (that's the one with which NASA's Deep Impact probe collided last
month). Swift-Tuttle returns every 130 years or so. In fact when it
was rediscovered in 1992, its orbital data didn't correspond with the previous
ones. Instead, a non-gravitational computation provided a better fit.
That sounds counter-intuitive at first since gravitation really is the
only force affecting orbits. But comets lose mass as solar wind pushes
away dust and gas - which we describe as a comet's tail or as a meteor shower -
and thus the gravitational force diminishes, changing a comet's orbit.
A new planet in our solar system has been discovered within the Kuiper belt, a
zone extending ten of billions of miles past Neptune's orbit, consisting of icy
remnants from the the original material that formed the solar system; many
short period comets come from this region. The object 2003 UB313 (a
catalog number akin to 109P) is currently a whopping 10 billion miles from Sun
and Earth on an orbit with an average distance of 6.8 billion miles, about
twice that of Pluto, its orbit is highly inclined at 44 degrees compared to the
other planets; it needs 557 years to revolve around our Sun. It's a
little bigger than Pluto, yet slightly smaller than our own Moon (hence Pluto
isn't very big either). This discovery has spawned once again a
discussion about what a planet is: there are no clear-cut criteria for the
definition of planet and it's not a scientific question but rather an
etymological one. Wikipedia.org points out that most definitions converge
on " that it [a planet] must orbit a star, be massive enough to become
spherical using its own gravity, and yet not big enough to produce nuclear
fusion in its core." However, even that is not clear cut, as many
moons are spherical and a few (our Moon, Jupiter's Io, Europa, Ganymede,
Callisto, Saturn's Titan) even bigger than Mercury, Pluto and 2003 UB313; there
are also rogue planets drifting through our galaxy that don't orbit a star.
On the other hand, since 1995 more than 150 extrasolar planets orbiting
other stars have been discovered, exclusively gas giants like Jupiter.
Personally, my response is non-chalant: any discovery and new development in
astronomy is so exciting that a question of definition is only secondary.
The Sky in May 2005
Astronomy nights are getting much shorter these days: from
11:30pm until 4:30am at the beginning of the month and from midnight until 4am
at month's end with twilight present pretty much the entire night. It
never gets really dark because even at local midnight at 2am on the Kenai, our
Sun is just ten degrees below the Northern horizon, so that sunlight from
beneath the horizon is brightening our atmosphere.
In early May find Saturn near Gemini's Castor and Pollux,
low in the West between 11pm and 1am; Jupiter appears all night low from South
to West. Venus and Mars are too low on the Western and Eastern horizon
during dusk and dawn, respectively. But these too will dominate the
evening and night skies next fall and winter. Uranus and Neptune are
visible before dawn, check Sky & Telescope's web site skypub.com for good
star charts of Aquarius and Capricornus. Pluto remains virtually elusive
for Alaskans as it's very low on the horizon during the summer months and on
top of that it's so faint that it requires at least a 16 inch telescope (not
mine, I max out at 8") that gathers enough light to make it visible.
Late in the month and throughout the summer only the
brightest stars will stand out: Spica and reddish Arcturus in the South
forming a large right triangle with Jupiter, rivaling the summer triangle
consisting of Vega, Deneb and Altair which starts to dominate the sky in the
East; Capella is low in the North. It will be tougher now to make out any
constellations besides the Big Dipper.
The Eta Aquarid meteor shower will be visible in the wee
hours on Thursday, May 5, when you can watch them emanating from a point above
the Eastern horizon. These meteors are debris ejected from Halley's
comet, spread out along its orbit. As they enter Earth's atmosphere at a
top speed of 150,000 mph, friction burns them up virtually completely and
that's the trails we can see.
So long for now, I'll be back in the fall.
The Sky in April 2005
Find Orion in the Southwest with Sirius, the brightest star, to
its lower left, Procyon and Castor and Pollux (the twin stars in Gemini) to its
upper left, Taurus with orangy Aldebaran and the star cluster Pleiades above
it, as well as Capella in its pentagon of Auriga very high in the West.
Watch for Saturn forming a small oblique triangle with
Castor and Pollux, now high in the Southwest as well. You'll see its
rings in a small telescope.
The Milky Way runs South to North this month. On the
Northern horizon find the bright stars Vega and Deneb. Notice also the W
of Cassiopeia inside the Milky Way in the Northwest, next to it the house of
Cepheus, then the Little Dipper, finally, almost in the middle (in the zenith),
the Big Dipper. Actually you would want to start with the Big Dipper
overhead anyway because its last two stars point to Polaris, the North Star, at
the end of the Little Dipper's handle, while the Big Dipper's own handle arcs towards
bright and orange Arcturus fairly high in the East. From there conclude
the journey with Jupiter left beneath Leo. A small telescope will reveal
its four large moons and perhaps its cloud bands.
The diagram shows the low Southern sky during the night of
April 23/24 (Saturday/Sunday) when Earth eclipses our Moon during a penumbral
partial lunar eclipse, lasting from 11 pm through 3 am. This is the least
desirable kind of eclipse: during an umbral lunar eclipse parts or all of our
Moon falls completely in Earth's shadow, but during a penumbral eclipse our
Moon still gets sunlight. In other words, an observer on our Moon would
see our Sun only partially eclipsed by Earth, so that quite a bit of sunlight
illuminates our Moon. Fred Espenak, NASA's most eminent eclipse expert,
writes on his web site: "Penumbral eclipses are difficult to observe.
Nevertheless, a subtle yet distinct shading should be visible across the
northern half of our Moon, especially during the one hour period centered on
maximum [around 1 am]." (Just type "espenak" on google and
you get great predictions, charts and information on all upcoming eclipses
around the world.) I take that as a challenge and figure that it'll be
worth observing this lunar eclipse - if for once somebody pushes those clouds
off the Kenai.
Eclipses come in at least pairs every half year: if you
happen to travel to the Southern United States or the Pacific side of South
America, you can see a partial solar eclipse on Friday, April 8.
Unfortunately Alaska is too far North for this one as our Moon's shadow
misses us.
Towards the end of the month Venus starts to emerge from our
Sun's glare: try finding it very low in the Northwest during dusk. Venus
will be an evening planet for the rest of the year.
Last but not least the morning sky: find Mars very low in
the Southeast before dawn (see inset). With binoculars you may be able to
find Neptune nearby, which is right above Mars around April 12. Uranus is
also visible with binoculars.
The Sky in March 2005
The diagram depicts the sky around 10 pm early in the month
and 8 to 9 pm in the middle of March, which is actually only one hour after
sunset; toward the end of the month more of the now Eastern constellations will
be visible and fewer of the Western. I also outlined a few prominent
constellations and labeled them with three latter abbreviations as well as the
brightest stars with a capital letter, and throughout the text and the diagram
look out for some special objects for binoculars (the darker your observing
site, the better), labeled with lower-case letters.
Three planets can be seen in the evening this month: Saturn finally
relinquishes its dominance, though due to its proximity to Castor and Pollux in
Gemini it's easy to find. Jupiter rises between 9 and 10 pm: you won't be
able to miss it because during this spring it'll be the brightest object in the
night time sky apart from our Moon. The diagram shows specifically the
evening of March 11: Mercury, the elusive inner planet, can be seen most easily
on that day because the thin sliver of our Moon is right next to it.
Mercury is otherwise hard to find because it's only visible very low on
the horizon during twilight and during this month's apparition there are
no other bright stars close by that could point to it. You can try
to find Mercury during the preceding week when it shows as a lonely point
in the deep blue sky and during the following week when our waxing Moon helps;
note though that our Moon has reached Saturn by the 19th. Since Mercury
orbits so quickly in only 87 days around our Sun, it's only visible in a
favorable position for a week or two at a time: during the evening this year in
March, July and November and during the morning this year in April, August and
December.
As far as the stars go, find Orion the hunter with red
Betelgeuse and blue Rigel in the Southwest with the "Orion nebula" (I
put these in quotes and use lower case letters on the map to point them out as
objects for binoculars) beneath the belt; then to its lower left Sirius, the
brightest star in the sky, then Procyon and Castor and Pollux, the twin stars,
to its upper left; finally the arrow shaped snout of the bull Taurus with
reddish Aldebaran including the star clusters "Hyades" and "Pleiades"
above it, as well as yellow Capella in its pentagon of Auriga almost overhead
which hosts three "open clusters". The visitor among these
bright stars of winter is Saturn, forming an obtuse triangle with Castor and
Pollux.
Other bright stars that are visible in the night sky include
Leo's Regulus high in the Southeast. The lion appearing in the evening
means that spring is right around the corner. There's also the faint
constellation of Cancer between Saturn and Regulus which hosts the pretty star
cluster Praesepe or "Beehive" and the yellow and blue double stars
"iota". Skimming the Northern horizon there is Arcturus in
Bootes in the Northeast, easily found because the Big Dipper's handle curves
toward it, as well as Lyra's Vega and Cygnus' Deneb (the Swan or Northern
Cross) in the North with the globular "Hercules cluster" nearby.
To conclude this tour find the Great Square of Pegasus in
the West with the "Andromeda Galaxy" and high in the sky the three
circumpolar constellations Ursa Major and Minor, aka Big and Little Dipper with
the double stars "Mizar & Alcor" in the bent of the Big Dipper's
handle and "Comet Machholz" near Polaris, and Cassiopeia, the Queen,
visible as a small W. Find just beneath the lower left portion of that W
the double cluster in Perseus. Since the comet is quite high I recently
had a young man in my Astronomy class lying down in the snow, so he wouldn't
have to crane his neck: he found the comet relatively easily. Note that
globular clusters, galaxies, nebulae, and comets all appear somewhat smudgy
with binoculars and small telescopes; the pictures you see published are long
time exposures taken through larger telescopes that are able to show much more
detail.
The Sky in February 2005
The diagram depicts the sky
around 9 pm in early February and about 8 pm later this month. I outlined
a few prominent constellations and labeled the brightest stars.
In the South find Orion the hunter with red Betelgeuse and blue Rigel and with
binoculars the Orion nebula beneath the belt; then to its lower left Sirius,
the brightest star in the sky, then Procyon and Castor and Pollux, the twin
stars, to its upper left; finally the arrow shaped snout of the bull Taurus
with reddish Aldebaran and the star cluster Pleiades above it (not labeled but
easy to find), as well as yellow Capella in its pentagon of Auriga almost
overhead.
The visitor among these bright stars of winter is Saturn forming an obtuse
triangle with Castor and Pollux. You'll see its rings in a small
telescope. The space probe Cassini arrived there last year and its
companion Huygens plunged into the atmosphere of its moon Titan just three
weeks ago. For images and scientific results of this mission I refer to
http://saturn.jpl.nasa.gov/home/index.cfm.
Other bright stars that are visible in the night sky include
Leo's Regulus in the Southeast. The lion appearing in the evening means
that spring is right around the corner. There's also the faint
constellation of Cancer between Saturn and Regulus which hosts the pretty star
cluster Praesepe or Beehive, a nice object with binoculars. Skimming the
Northern horizon find Arcturus in the Northeast as well as Lyra's Vega and
Cygnus' Deneb (the Swan or Northern Cross) in the Northwest. The latter
are part of the summer triangle (Altair which would complete the triangle is
beneath the horizon). As the name suggests it's a pattern of stars
visible in the summer but in Alaska we're so far North that some constellations
like Lyra and Cygnus are visible year around. However, while we're
gaining some Northern constellations we're also losing some Southern
constellations, hence Sirius' Canis Major, the Big Dog, is barely above the
Southern horizon.
To conclude our meanderings of the sky find the Great Square
of Pegasus in the West and high in the sky the three circumpolar constellations
Ursa Major and Minor, i.e. the Big and Little Bear aka Big and Little Dipper (I
labeled Polaris, the star that always stays put), and Cassiopeia, the Queen,
visible as a small W. Again using binoculars, find just beneath the lower
left portion of that W the double cluster in Perseus and if you peruse the sky
nearby you may also find Comet Machholz. Their appearances as smudgy
objects is really similar which is why more than two hundred years ago the
French comet hunter Charles Messier set out to catalog a lot of smudgy objects
(such as M45 Pleiades, M44 Beehive, M42 Orion nebula - the Perseus double
cluster would have been worthy making the list but Messier just didn't include
it), so that they would not be confused with comets.
The winter sky is impressive, especially the Southern
portion, because of the 25 brightest stars in the entire sky 13 are visible
right now (I didn't label Taurus' Elnath nor Orion's Bellatrix) and another 10
from the next 25 brightest stars which includes the mentioned Castor and
Polaris, itself number 48, as well as some stars from the Big Dipper, Auriga,
Gemini, Canis Major and Perseus.
If you're a night owl wait for Jupiter to rise just before
midnight. If you're an early riser look out for Jupiter as well, by then
it's high in the South, and for Mars which rises around 4:30 am in the East.
Although it's cold outside you may see me occasionally
stargazing somewhere, for example right now I'm offering a casual astronomy
class through community schools for another three Tuesdays in February and
March with the next meeting on February 15 (contact Carmen Triana at 262-6768).
The Sky in January 2005
The view is toward
Southeast around 9pm throughout January. The dominating constellation is
Orion the hunter. It is many people’s favorite because of its
brilliance. Four stars arranged in a rectangle (with red Betelgeuse in
the upper left, blue Rigel in the lower right, Bellatrix, and Saiph) outline
the body, while three stars make up the belt with the Orion nebula as the sword
beneath it. Above Orion you find Taurus, part of it in the shape of an
arrowhead including red Aldebaran. And above that are the Pleiades star
cluster (just outside the diagram), also called the Seven Sisters, a must for
binoculars with which you can see 30 to 50 of its total of 500 stars. To
Taurus’ left is the pentagon Auriga with yellow Capella (also just
outside the diagram). Beneath Capella appear Castor and Pollux, the twins in Gemini, accompanied by Saturn
this winter. And then we close this circle toward the horizon, with Procyon and
the Number One: Sirius, the brightest star in the entire sky, just rising in
the diagram. Jupiter will rise as late as 2am; it and Mars are also
visible in the morning sky while Venus and Mercury make a nice double low on
the Eastern throughout the first two weeks of January.
Also in the diagram is a dashed line depicting Comet Machholz. It
is moving almost tail first* through Taurus during the first two weeks, then
through Perseus. It's as bright (or faint) as the fainter stars in those
constellations and shows as a fuzzball in binoculars, though its tail shows up
only on 1 minute photos. In very darks areas, for example for skiers
staying in a remote cabin on the Kenai, it can be viewed with the naked eye,
almost as bright as the Andromeda galaxy. (* when a comet enters the
inner solar system, our Sun's solar wind is strong enough to evaporate gas and
dust from the comet producing the famous tail; that tail is pointing away from
our Sun and it is thus not an indicator of the comet's direction)
Among the stars of winter is the intruder Saturn looking forward to being in
the news this month. It's most interesting moon is Titan, large and cold
enough - minus 290 oF - to make it the only moon in the solar system
that retains an atmosphere. That atmosphere consists primarily of
Nitrogen and Methane (CH4), and furthermore beneath its thick cloud
cover, lakes and perhaps oceans of Methane may exist and it might constantly
rain this liquified gas. This scenario on Titan may provide the best
conditions in our solar system for something very precious: life. Albeit
of course, any such hopeful discovery would mean microorganisms that may be
quite different from what we're used to, having adapted to those frigid
temperatures. By now the space probe Huygens has separated from its
mother ship Cassini (which will continue orbiting Saturn). On January 14
it will plunge through Titan's atmosphere and perhaps will float in its Methane
ocean, sending data from the moon's surface.
The Sky in December 2004
I will offer astronomy mornings
throughout most of the week of December 6 (Nikolaus Day, so shine your shoes),
that is Monday through Thursday, 7:30 am until 9:00 am (that’s when
morning twilight starts), on the KPC parking lot, off College Drive or Poppy
Lane from Kalifornsky Beach Road. This is a good winter for this
winter's morning planets - Venus, Mars, Jupiter, and Saturn - and of course I
can organize such an event at a reasonable morning time in
- Mercury is not visible during that particular week but will appear very close to Venus on and around the 29 th . We will therefore look for the following planets.
- Very bright Venus will be visible near the Southeastern horizon until January.
- Mars will be above Venus with the two being just one degree apart on the 5th, all the while Venus passing Mars and closing in on our Sun. Mars will then be visible in the morning for the entire winter and spring, appearing more and more toward the West, showing up in the evening sky not until October of next year.
- Bright Jupiter will climb higher each month, appearing in the South until January and Southwest until February; since Earth’s rotation is continuous (throughout the night), Jupiter will also be visible in the evening sky starting in March. A special event this month occurs in the wee hours of December 7th but only east of the Rocky Mountains: the third quarter Moon will occult Jupiter, so let your friends and relatives back east know about that. We will see our Moon beneath Jupiter on the same morning after the occultation is over.
- Saturn has been visible near Gemini’s bright twin stars during both evening (in the East) and morning (in the Southwest) for a while and will be exclusively an evening planet starting in February.
- Uranus and Neptune have been
evening planets throughout fall but are now too low to be seen in
I also chose this
particular week because the third quarter moon will be visible in the morning with
its sliver appearing near Venus and Mars on the 9 th .
An interesting factoid for this month:
all planets from Mercury to Pluto are arranged in the proper order westward
from our Sun as seen in Earth’s sky, a pattern occurring for the first
time in two hundred years. Other than being an interesting factoid there
is no astronomical or any other significance attached to this.
The accompanying diagram shows the sky around 8:30 am
in early December (7:30 am later in the month). Thus this diagram depicts
the morning sky for a change because of the planets showing up. Notice
that the descriptions in the following paragraphs refer to the evening sky and
therefore constellations appear in different parts of the sky, respectively
some constellations will have set already in the morning.
As for the evening sky, the stars of winter are back, rising
in the East. The dominating constellation is Orion the hunter. It is many
people’s favorite because of its brilliance. Four stars arranged in
a rectangle (with red Betelgeuse, blue Rigel, Bellatrix, and Saiph) outline the
body, while three stars make up the belt with the Orion nebula, a stellar
nursery, as the sword beneath it. Above Orion you find Taurus, part of it
in the shape of an arrowhead including red Aldebaran. And above that are
the Pleiades star cluster, also called the Seven Sisters, a must for binoculars
with which you can see 30 to 50 of its total of 500 stars. To
Taurus’ left is the pentagon Auriga with yellow Capella. Beneath
Capella appear Castor and Pollux, the twins in Gemini, this winter forming
almost a line with Saturn. And then we close this circle towards the horizon,
with Procyon and the Number One: Sirius, the brightest star in the entire
sky. This month's Astronomy magazine shows a sky map of the same region
with 27 interesting stars, nebulae and clusters labeled (check out the
libraries for the current issue).
Find the Big Dipper on the Northern horizon, the Little
Dipper high in the North as usual, Cassiopeia's W almost straight up. In
the West is the summer triangle comprised of the bright stars Vega, Deneb, and
Altair in the constellations Lyra the harp, Cygnus the swan (looking like a
cross) and Aquila the eagle, left of which is the small constellation Delphinus.
High in the South is Pegasus' Great Square.
The Sky in November 2004
Winter has almost arrived and that means that the bounty of the beautiful
winter sky charmes us once more. The accompanying chart is set for 10pm in
early and midnight in late November, thus more stars will have risen in the
earlier evening hours later this month. Finally Orion, Taurus, Gemini and
Auriga are rising in the East. With them are the bright stars of winter:
red Betelgeuse and Aldebaran, blue Rigel , yellow Capella and next to the
twins' Pollux and Castor appears Saturn, its rings nicely seen in a small
telescope. Also included is the star cluster of the Pleiades, best viewed
with binoculars when up to 50 stars may be seen. Soon the bright stars
Procyon and Sirius will follow. Now in the Zenith are Cassiopeia's W and
the House of Cepehus. Always in the same place is the Little Dipper with
Polaris and toward the Northern horizon appears the Big Dipper. The
kite-shaped Bootes is now setting while the summer triangle consisting of Deneb
(the Swan's tail), Vega and Altair is getting closer to the Western horizon but
will be visible until January since Deneb and Vega are circumpolar in Alaska
(they never set).
The morning sky still holds its splendor with Saturn high in the South now
close to the twins of course and I expect that the number of IFO sightings will
go up when Venus and Jupiter pass each other during the first week of the month
with closest approach on the 4th while on the morning of the 9th the crescent Moon
joins Jupiter when they bid farewell to Venus which will slowly retreat into
twilight.
For last month's partial solar eclipse we were unfortunately clouded in, though
I had a good time visiting with people on Bridge Access, and by the time of
writing this I don't know how the weather was for the lunar eclipse. But
you may still join me for the Halloween evening viewing in Soldotna Creek Park,
today, Sunday October 31st, 8-10pm.
The Sky in October 2004
This may be the month of the year for observing, at least as
far as special events are concerned. Now that we’re past the
equinox, nights are getting darker and longer. I know it’s getting
colder too but there’s still plenty to do in the outdoors, soon we’re
back to skiing, skating and snow-machining during the short days, and of course
Astronomy at night, best with some hot chocolate.
There’ll be a partial solar eclipse on Wednesday,
October 13, visible in Japan and the western portion of North America.
The eclipse starts in the afternoon at 6 pm and is still in progress at sunset
just one hour later, with a maximum of 75% eclipsed at sunset. It is thus
preferable to have a non-obscured view to the West. Of course, you would
have to have special eclipse glasses. I’ll be at the turn-out on
Bridge Access with telescopes (equipped with appropriate solar filters) and
plenty of solar eclipse glasses. Join me there.
A total lunar eclipse is observable from almost everywhere
in the Americas and most of Europe, Africa and Western Asia on Wednesday
evening, October 27. Obviously, this is when we have full Moon. And
lunar and solar eclipses (about 2 or 3 every six months) are the only times
when there are any shadows involved! I emphasize this because shadows
have absolutely nothing to do with, never will, and are completely, irrevocably
unrelated to our Moon's phases.
The eclipse has already started when our Moon rises at 6 pm
just North of East. This is a naked eye and/or binocular event but again
I’ll be at Bridge Access with telescopes until about 9 pm.
Bridge Access isn’t by far the best place to do
astronomy but the cars driving by are hardly bothersome for eclipses because
eclipses don’t need darkness; and of course that site has good views
toward both West and East. There were quite a few people during last
November’s total lunar eclipse at the same site, everybody parking facing
East.
The above viewing is of course weather permitting. If
the weather doesn’t cooperate, I won’t be able to reschedule these
events ;-) In that case we’d have to wait until next April and
October for the next lunar eclipses and until March 2007 for the next partial
solar eclipse. So let’s cross our fingers for the ones this month.
If you want to know more about eclipses, search for
"Fred Espenak" (he's NASA's eclipse guru) on google.com. Find
some eclipse animations on my web site,
http://www.wncc.net/courses/aveh/lecture/lecmove.htm. Give me a call at
262-0366 at KPC if you have further questions.
The planets put on quite a show too: for early risers, watch
Jupiter joining Venus above the Eastern horizon during dawn, a conjunction of
the brightest two objects in the sky (after our Sun and our Moon). Saturn
is quite high in the Southeast before and during dawn, near the bright stars
Castor and Pollux in Gemini.
Uranus and Neptune can be viewed low in the South for most
of October. They’re harder to find and I advise to check with
astronomy magazines in the libraries. Respectively, I will probably take
my students to the public access beach near the Kenai Landing during the
evenings (after dusk) of either Wed, October 6 or Sat, October 9.
The stars of fall are back: this time I highlighted easy to
find constellations such as the Big Dipper, the fainter Little Dipper, kite-shaped
Bootes, W-shaped Cassiopeia, house-like fainter Cepheus, cross-like Cygnus, the
Summer Triangle (dashed line), the Great Square of Pegasus, the arrow-like
snout of Taurus, pentagon-shaped Auriga. I also just highlighted the
brightest stars, red Aldebaran in Taurus, yellow Capella in the Northeast, the
twins Castor and Pollux on the NE horizon, red Arcturus in Bootes (the Big
Dipper's handle points to this star), and Deneb, Vega and Altair that make up
the summer triangle. The arrows show the direction in which the stars
seemingly turn because of Earth rotating in the opposite direction under the
stars. That means that stars set in the West and new ones rise in the
East during the night.
The Sky in September 2004
Uranus and Neptune are the evening planets this month,
appearing very low in the South to Southeast in the late evening. How to
find Uranus: first of all binoculars are advised. Also, check out
skypub.com or similar oberving web pages or the April through September 2004
issues of Astronomy and Sky & Telescope magazines at the Kenai, Soldotna
and KPC libraries. They feature charts and information that is easier to
follow than I could describe here.
Both planets are faint and just on the brink of being
observable with the naked eye, hence my advice for binoculars which are
sufficient. Best observing time in September is around midnight and best
observing place may be a beach on Cook Inlet with unobstructed view towards the
South; that's because they're just 15 degrees above the Southern horizon.
The planets are in the faint constellations of Aquarius and Capricornus which
makes it actually easier - in my opinion - to spot them because there are
plenty of faint stars to compare them to. As I indicated, the charts in
those publications listed will help you find them. How do you know which
is a planet? For one, Uranus itself should show a hint of green through
binoculars; Neptune's bluish tint probably won't show. And then, you'd
make an observation one night and come back a week later and you'll notice that
the planets will have retrograded to the right.
Other planets are accessible in the morning before sunrise. All month long
look for bright Venus above the Eastern horizon. Early in the month
notice Saturn as well as the twin stars Castor and Pollux just above of
Venus. Throughout September, Venus will then move away from Saturn into
Cancer and Leo. The accompanying drawing shows a view due East around
September 10 when these planets are joined by our waning crescent Moon.
Around those dates wait until dawn and find Mercury rising on the Eastern
horizon.
Jupiter and Mars are not visible this month but will become
morning planets later this fall.
For the stars themselves, here is a rehash - since we are
now able to actually see stars in once again dark environs; this is for the
evening sky. To first orientate yourself first, find the Big Dipper low
in the Northwest; then extend the dipper's last two stars high into the North
to find Polaris, the North Star, and the Little Dipper; with the Big Dipper on
one side of Polaris, find the constellation Cassiopeia, a nicely shaped W, on
the other side of Polaris high in the Northeast. Back to the Big Dipper,
follow the curve of its handle towards the bright Red Giant Arcturus low in the
West with its constellation of Bootes above, appearing as a kite or cone
shape. Notice the bowl shaped Corona Borealis to its upper left.
Prominently high overhead and extending to the South is the Summer Triangle,
made up of the three bright stars Vega, Deneb and Altair. Deneb's
constellation of Cygnus, the Swan, in a cross shape is easily seen; Vega's
small rectangular shaped Lyra, the Harp, is prominent as well; while Altair's
Aquila or Eagle may be depicted by its wings. But just on the upper left
of Altair is the dolphin shaped small constellation Delphinus. Also
prominent in the Southeast are the Great Square of Pegasus and low in the
Northeast bright yellowish Capella with its pentagon shaped constellation
Auriga. By morning, constellations have rotated towards the West with
some of them having set while other have risen in the East. Those are
Orion, Taurus, Gemini, Cancer and Leo as well as the planets described above.
Have fun observing, I'm looking forward to hopefully clear
skies this winter and the Astronomy class I'll be teaching this fall.
The Sky in July 2004
This month's major event isn't really observed in the sky but rather on TV, in
the papers and on the internet: for the first time in 23 years - since the
Voyager probes - the man made space probe Cassini is arriving at Saturn,
guaranteed to give us extraordinary photos and research opportunities.
Cassini - so named after the 17th century Italian observer Giovanni Cassini who
discovered four of Saturn's moons and the famed division in the rings that
bears his name - has been en route since its launch almost seven years
ago. Aside from making news for carrying Plutonium with it to generate
electricity, it's been on an incredible journey with two Venus flybys, one
Earth and one Jupiter flyby that were used as gravity assists in order to
conserve fuel. Now it's finally arrived and it's time to be inserted into
an orbit around Saturn.
The size of a mini-van, Cassini is the largest man made planetary probe ever
launched. It's anticipated to send half a million photos of Saturn, its
rings, and its 31 moons back to Earth during the next four years; about 260
scientists from 17 countries are participating in the evaluation of the data
that it sends back as well.
Saturn's most interesting moon is Titan, large and cold enough - minus 290 F -
that it is the only moon in the solar system that retains an atmosphere.
That atmosphere consists primarily of Nitrogen and Methane (CH4), and
furthermore beneath its thick cloud cover, lakes and perhaps oceans of Methane
may exist and it might constantly rain this liquified gas. This scenario
on Titan may provide the best conditions in our solar system for something very
precious: life. Albeit of course, any such hopeful discovery would mean
microorganisms that are completely different from what we're used to, having
adapted to those frigid temperatures.
To hopefully supply answers, Cassini will deploy another probe - Huygens, so
named after the 17th century Dutch physicist Christian Huygens who actually
identified Saturn's rings as such - in December. Huygens will plunge
through Titan's atmosphere and perhaps will float in its Methane ocean, sending
data from the moon's surface.
As I mentioned, this will be armchair astronomy for us. But at the end of
August, the early risers among us will be able to see Saturn again low in the
Eastern sky during pre-dawn hours. At that time, it's easy to find
because Venus appears right next to it.
And as far as Venus is concerned, it may be the only planet visible throughout
July, very low but bright in the Northeast, very, very early around 3 am when
even on the Kenai it's "dark" enough to make out a bright
planet. Venus has by now recuperated from last month's historic
transit in front of the Sun, the first in 122 years, leading to the next in
eight years, not to be repeated after that until the year 2117.
The Venus
Transit was visible from Europe, Asia, Africa and the East coast of N.
America because they had daylight. But of course Alaska has a lot of
daylight, so I went to Barrow and had success. I hooked up with six other
enthusiasts, we set up our gear and peeked on and off through the constant haze
surrounding Barrow during the six hour transit. Our photos can be seen on
my web site http://chinook.kpc.alaska.edu/~ifafv/lecture/lecsky.htm where I also
supplied some links to Cassini and Saturn related web sites.
Voyager Saturn Science Summary :
http://www.solarviews.com/eng/vgrsat.htm
Cassini Huygens Home at JPL
: http://saturn.jpl.nasa.gov/index.cfm
Cassini's
Plutonium is safe :
http://www.planetary.org/news/Cassini/hot-top-cassini8.html
Saturn facts: http://www.solarviews.com/eng/saturn.htm
, http://www.nineplanets.org/saturn.html
Titan facts: http://www.solarviews.com/eng/titan.htm
, http://www.nineplanets.org/titan.html
Venus
Transit in Barrow : http://24.237.160.4/files/Astronomy/MyPhotos/venus-transit-2004/
The Sky in June 2004
Dark nights are virtually non-existent, though some bright stars and planets
can be seen, especially around local midnight which is at 2:00 am, when our Sun
is lowest beneath the horizon and the sky takes on its darkest blue hue.
The brightest of those planets should be Jupiter in the West, among the stars
Vega and Capella should be visible in the East and North. And as Venus is
in inferior conjunction, i.e. between us and our Sun, it should not be visible.
But this is the month for the famed Venus Transit.
The magic date is June 8, 2004.
However, since Alaska is situated in a very Western time zone, for us
it's the evening of the 7th leading into the 8th. On the 7th starting at
9:15 pm Venus will glide across the Sun's face for the ensuing six hours: a
Venus Transit - the last such event occurred in 1882. It is a rare but
very predictable event, and in past centuries a Venus Transit had astronomical
significance: the distance Sun to Earth could be determined.
While a Mercury Transit happens every
seven years on the average, though right around now they occur rather often in
1999, 2003 and 2006, Venus Transits are indeed very rare as they come in pairs
eight years apart and then again either 105 or 121 years later. Venus
orbits our Sun every 224 days and passes Earth every 584 days. But since
Venus' orbit is tilted by 3.4 degrees with respect to the Earth's orbit, Earth,
Sun and Venus are rarely lying exactly on a straight line. That's only
the case when Venus is exactly at its nodes, where its orbit crosses the plane
of the Earth's orbit, and we're viewing Venus and Sun together.
The Venus Transit can be seen from Europe, Asia and most of Africa as well as
parts of Eastern N. America because it happens during their daytime. Of
course, in Alaska daytime is extended into the night and the further North you
travel, the more you can see it as our Sun skims along the horizon.
You may view the Venus Transit safely with special solar eclipse glasses, or,
according to the August 1999 issue of Sky & Telescope , welder's
filters of shades 14 and higher may be used. Other so-called filters may
not be safe (of course, regular sun glasses are out of the question) and may lead
to temporary or permanent eye damage. And, under no circumstances, use
binoculars or a telescope to view our Sun, not even with the safe solar
filters: the larger lens or mirror will intensify our Sun's light and burn a
hole right through the solar filter and then through your retina! You
have to make do with the small image that the eclipse glasses or the welder's
filter will give you. And, in any case, just to be on the safe side, use
caution and since you're inexperienced , do not look at our Sun for too long
with the safe solar filters.
In 1627 German astronomer Johannes Kepler became the first person to predict a
Venus Transit, having achieved the mathematical feat with the help of his newly
discovered Laws of Planetary Motion. He predicted the upcoming transits
for 1631 and 1639, though he died a year prior to seeing one himself - and the
1631 transit wasn't visible from Europe anyway. On December 4, 1639, the
English Jeremiah Horrocks and William Crabtree were the first to view a Venus
Transit, using the projection method. Fortunately they had recalculated
Kepler's computations and found that the transit would occur a few hours before
Kepler's predictions, otherwise they would have missed it. Still, it's
quite an accomplishment for Kepler to have computed a transit twelve years
prior with such a high accuracy. And this was before hand-held
calculators were available.
A hundred years later Edmund Halley proposed that a Venus Transit could be used
to determine the scale of the solar system since observing a transit from
different vantage points on Earth would yield slightly different observing
times and using parallax and simple trigonometry, distances in the solar system
could be measured.
Several expeditions were sent out for the June 1761 and 1769 transits.
Some met with misfortune, such as Guillaume LeGentil's mission who in
1761 had to observe the transit from a ship during heavy seas on the Indian
Ocean - the French frigate could not land in Pondicherry, India, because the
English had just occupied the region. In 1769, after having built an
observatory in India, he encountered cloudy skies during the day of transit.
Others were more successful, such as the Americans John Winthrop in
Newfoundland and David Rittenhouse in Pennsylvania; James Cook himself on the
island of Tahiti. One of the scientific accomplishments was the discovery
by the Russian Mikhail Lomonosov in St. Petersburg in 1761 that Venus has an
atmosphere as sunlight was slightly smeared around the edges of Venus. That
though proved a drawback for timing the transit exactly because a smeared image
doesn't make for accurate measurements. Compiling all measurements though
led to a Sun-Earth distance of 95.4 million miles, which was the standard used
until the December 1874 and 1882 transits when photography aided astronomers
and a corrected figure of 92.8 million miles was accepted. Newer
measurements using radar give an average distance of 93.0 million miles, 91.4
in January and 94.5 in July.
In my quest to get as far North as I can and to have an unobstructed Northern
horizon, I will pack a small telescope with proper filter, binoculars with
proper filters, two projection screen telescopes, and some eclipse glasses and
head on the Dalton Highway towards the Tors near Finger Mountain, just 18 miles
short of the Arctic Circle. I also have a plane ticket to Barrow but the
weather prospects aren't good; actually they aren't good near Fairbanks either.
From the Kenai the first two hours of the transit can be observed but
then our Sun sets around 11 pm on the 7th.
The Sky in May 2004
Astronomy nights are getting much shorter these days: from 10pm until 6am at
the beginning of the month with twilight reducing the time by an additional
hour and from 11pm until 5am at month's end with twilight present pretty much
the entire night. It never gets really dark because even at local
midnight at 2am on the Kenai, our Sun is just seven degrees below the Northern
horizon, so that sunlight is lighting our atmosphere.
In early May find Saturn, Mars and Venus clustered low in the West and NW
between 11pm and 1am; Jupiter appears all night low from South to West.
Late in the month we can only find Jupiter low in the West after
midnight, joined by our Moon on the 27th, while our Sun has crouched in on the
other three planets; actually if you can find crescent moon very low in the NW
around midnight on the 21st, try for the three planets as well when they're
clustered around it.
However, Venus poses a nice sight earlier in the month if you have a telescope:
you will be able to make out its crescent shape which takes its form due to its
proximity to our Sun and the geometrical relationship with us.
Late in the month and throughout the summer only the brightest stars will stand
out: Spica and reddish Arcturus in the SW forming a large right triangle with
Regulus and Jupiter in the West, Capella low in the North, and the summer
triangle consisting of Vega, Deneb and Altair starts to dominate the sky in the
SE. It will be tougher now to make out any constellations besides the Big
Dipper. By the way, Capella in the North tells us that we're living so
far North because around here it's circumpolar, i.e. it never sets, while in
the Lower 48 it's gone in April and will emerge in the fall again.
As described in the May issues of Astronomy and Sky & Telescope magazines,
both available in our public libraries and e.g. at Freddies as well as on the
internet, two naked eye comets can be seen this month. But I refer you to
these publications for more information since I don't want to describe
something in detail that unfortunately will be hard to see from Alaska and even
from downsouth because they're very close to the horizon near the winter
constellations of Canis Major and Orion. Thought I'd mention it though.
And to add to this, a lunar eclipse would be visible May 4 if
But hang on for the Venus transit on June 7th/8th when Alaska becomes the only
place in the US to see this twice-in-a-lifetime event, all of it from north of
Fairbanks, though partially visible from the Kenai.
The Sky in April 2004
Even though the nights are getting considerably shorter, we'll still have a
great planet show going on this month.
Four planets are dominating the evening sky with a fifth being barely visible
really early in April. In the early evening look for ultra-bright Venus
high in the West. Then as evening advances, find Orion in the Southwest
with Sirius, the brightest star, to its lower left, Procyon and Castor and
Pollux (the twin stars in Gemini) to its upper left, Taurus with orangy
Aldebaran and the star cluster Pleiades above it, as well as Capella in its
pentagon of Auriga very high in the West.
Watch for Saturn forming a long triangle with Castor and Pollux, now high in
the Southwest as well. You'll see its rings in a small telescope.
Between orange Aldebaran and left next to Venus find another red object
of a different kind: Mars.
The accompanying diagram shows the sky at about 10pm Alaska Daylight Savings
Time (ADT). All the bright stars and planets just described cluster
around the word "Saturn."
The Milky Way runs South to North where, on the Northern horizon, you find the
bright stars Vega and Deneb. Notice also the W of Cassiopeia inside the
Milky Way in the Northwest, next to it the house of Cepheus, then the Little
Dipper, finally, almost in the middle (in the zenith), the Big Dipper.
Actually you would want to start with the Big Dipper overhead anyway because
its last two stars point to Polaris, the North Star, at the end of the Little
Dipper's handle, while the Big Dipper's own handle arcs towards bright and
orange Arcturus fairly high in the East. From there conclude the journey
with Jupiter right beneath Leo. A small telescope will reveal its four
large moons and perhaps its cloud bands.
I mentioned some orange and red stars: Arcturus and Aldebaran as well as
Betelgeuse in Orion's left shoulder are red supergiants (so is Antares in
Scorpius, an early fall constellation). Almost all stars appear white to
us because the human eye cannot perceive their colors in the blink of an eye
while a long exposure photo picks up colors much better. It turns out
that many stars are actually white but many others are blue, yellow (guess
which), orange, and red. Only the brightest colored stars will exhibit
their color to the naked eye; notice that a rifle scope may produce too much
refraction, making all stars twinkle very colorful - these are not the stars'
colors. The above mentioned four stars should appear definitely red.
Rigel in Orion's right foot should appear blue and Capella appears yellow to
some people. The colors of stars depend on their surface temperature:
blue Rigel at 20,000 F, white Sirius at 17,000 F, yellow Sun and Capella at
10,500 F, orange Arcturus and Aldebaran at 7,500 F and red Antares and
Betelgeuse at 6,000 F. Since the latter four are huge stars, their
stellar atmospheres being a thousand times larger than our Sun's, they are also
very bright despite being rather cool.
The Sky in March 2004
This month
there are four planets dominating the evening sky with a fifth joining them
later in the month. In the early evening look for ultra-bright Venus high
in the Southwest. Then as evening advances, find Orion in the South with
Sirius, the brightest star, to its lower left, Procyon and Castor and Pollux
(the twin stars in Gemini) to its upper left, Taurus with reddish Aldebaran and
the star cluster Pleiades above it, as well as Capella in its pentagon of
Auriga almost overhead.
Watch for Saturn forming a long triangle with Castor and Pollux, now high in
the South as well. You'll see its rings in a small telescope.
Between Venus and red Aldebaran find another red object of a different
kind: Mars.
The accompanying diagram shows the sky at about 8pm. All the bright stars
and planets just described cluster around the word "Saturn."
The Milky Way runs Southeast to Northwest and the cross signifies Polaris
at the end of the Little Dipper.
To round out this pearl string of planets, bright Jupiter in Leo becomes
visible around 8pm. A small telescope will reveal its four large moons
and perhaps its cloud bands. Jupiter is also the one that you see when
driving to work in the pre-dawn hours, by which time it has moved towards the
Western horizon; of course it's Earth that has rotated that much.
Moving back, East to West through the Zodiac, we see Cancer with the Beehive
star cluster between Leo and Gemini (Saturn again), Taurus, then inconspicuous
Aries (Mars again) and Pisces (with Venus) where we find the Great Square of
Pegasus above Venus with faint comet Linear C/2002 T7 on the left side of
Pegasus. The comet's faint coma can be seen with binoculars. Comet
discoveries used to be almost the sole domain of amateur astronomers because
they would scan the entire sky to look at interesting objects and then more or
less accidently stumble across a huge snowball. The new comet then got a
catalog number and was also named after their discoverers, thus such great
names such as Halley, Hyakutake, Hale-Bopp, Schwassmann-Wachmann,
Temple-Tuttle, Swift-Tuttle, Shoemaker-Levy 9, Ikeya-Zhang, leading to an
average 50 per year; but most of them cannot be seen by the naked eye.
However, since the late 90s professional astronomers started looking as
well mostly in conjunction of cataloging near-earth-objects (for obvious
reasons; fortunately no hazardous ones have been detected so far). And so
comets are named more and more after their team names, such as this one where
Linear stands for MIT's Lincoln Near Earth Asteroid Research project which has
discovered 133 comets so far since 1998, an average of almost two per month.
So grab your binoculars and enjoy this comet.
There are also bright Vega and Deneb low in the Northwest, the Big Dipper high
in the Northeast with its pointer stars pointing at Polaris the North Star.
The latter is at the end of the Little Dipper's handle, sixty degrees
above the Northern horizon, matching the Kenai's latitude.
Mercury can be glimpsed at month's end, probably between 8 and 9 pm. At that
time, it's getting dark much later but don't wait too long because Mercury sets
early still, not long after our Sun. From about the 23th through April
4th draw an imaginary line from Mars through Venus (they've closed in on each
other in Taurus) to the West-of-Northwest horizon to find Mercury very low.
Locating our Moon near Mercury would help too, however, the two appear
very close to each other on the 21st and 22nd when our Moon is only one
and then two days old (past new moon) and that crescent is probably impossible
to glimpse during dusk. On the 29th of March, both Mercury and Venus
reach their largest separation from our Sun.
Our Moon is full on the 6th, appears next to Jupiter on the same day, is
closest and thus biggest to Earth on the 11th while it's a half moon.
It's new on the 20th, a waxing crescent below Venus on the 24th and to
the lower right of Mars on the 25th, while farthest and hence smallest as a
half or first quarter moon on the 26th, and it finally reaches Saturn on the 28th.
As days are getting very quickly longer, we pass through the equinox on the
19th.
The Sky in February 2004
If
it wasn't for all the bright stars that we have been able to enjoy all winter,
three to four planets would dominate the evening sky. In the early
evening, even during dusk, look for ultra-bright Venus in the Southwest.
Then as evening advances, find Orion in the Southeast with Sirius, the
brightest star, to its lower left, Procyon and Castor and Pollux to its upper
left, Taurus with reddish Aldebaran and the star cluster Pleiades above it, as
well as Capella in its pentagon of Auriga almost overhead.
Watch for Saturn forming a long triangle with Castor and Pollux, now high in
the East. You'll see its rings in a small telescope. Between Venus
and red Aldebaran find another red object of a different kind: Mars.
The rusty planet has been invaded for the past month by the British lander
Beagle 2 (which unfortunately was lost), the American landers Spirit and
Opportunity and the European orbiter Mars Express. The latter has been
able to capture the highest resolution images ever and its first photos of
miles long sediments are yet the strongest evidence that once liquid water
existed on Mars.
To round out this pearl string of planets, bright Jupiter will rise in the
Northeast during late evening. A small telescope will reveal its four
large moons and perhaps its cloud bands. Jupiter is also the one that you
see when driving to work in the pre-dawn hours, by which time it has moved towards
the Western horizon; of course it's Earth that has rotated that much.
Back to the evening skies: other easy to see constellations are the Great
Square of Pegasus above Mars, bright Vega and Deneb in the Northeast, the Big
Dipper in the North with its pointer stars pointing at Polaris the North Star.
The latter is at the end of the Little Dipper's handle, sixty degrees
above the Northern horizon, matching the Kenai's latitude. With Jupiter
are also rising Leo and Cancer. From dark areas you may also enjoy the Milky
Way running East to West.
Our Moon is full on the 5th, appears above Jupiter on the 7th/8th, closest and
thus biggest to Earth on the 15th, although it's a waning crescent then in the
morning sky. It's new on the 19th, a waxing crescent below Venus on the
22nd and beneath Mars on the 24th, while farthest and hence smallest as a half
or first quarter moon on the 27th, and it finally reaches Saturn on the 29th.
And because Earth rotates on its axis almost exactly 366.25 per year as we
orbit our Sun, we usually have 365 days (minus one rotation matching the orbit,
hence the at first puzzling 366) and every four years we insert the accumulated
4 x .25 = 1 extra day as February 29th.
The Sky in January 2004
I
must reiterate what I wrote in last month's column: enjoy the beautiful winter
sky of Orion, Taurus, Gemini, Auriga with Betelgeuse, Rigel, the Orion nebula,
Aldebaran, the Pleiades and Hyades star clusters, Capella, Castor and Pollux
Procyon, Sirius, all above the Southern horizon. Look out for aurorae as
well and every twenty minutes or so get a hot chocolate or hot spiced wine.
Find Saturn in Gemini rising in
the early evening. Notice how the ringed planet retrogrades throughout
January, starting out as an equilateral triangle with Castor and Pollux, then a
right triangle as it moves away and up. Watch for really bright Jupiter
in Leo in the East [see diagram], rising around 10 pm; reddish Mars low in the
Southwest just West of Taurus and beneath the great Square of Pegasus, all
evening long until it sets around 10pm; superbright Venus low in the Southwest
in the early evening.
Look for the summer triangle made up of Vega, Deneb and Altair setting in the
West. It sounds like a misnomer: during summer those three stars are the
most prominent, but they can still be seen well into January; indeed, in Alaska
both Vega in Lyra, the Harp, and Deneb in Cygnus, the Swan or Cross, are
circumpolar, that is they never set and can be seen as two bright stars on the
Northern horizon in the middle of the night. As for the others, look for
the Big Dipper fairly high in the Northwest, its pointer stars in the bowl
poiting to Polaris which itself is the last star in the Little Dipper's handle,
then look for Cassiopeia, the Queen or W, virtually overhead. Check out
skymaps.com for monthly sky charts and events.
Special events in January: Earth is closest to our Sun on January 4th at a
whopping 91,400,177 miles, compared
to July 5th when we're 94,507,582 miles away; the seasons are caused by Earth's
axis tilt which is why we get low arcs of our Sun's path and short days from
October through February; the difference in distance would be too small anyway
to cause such differences in seasons; around January 14th use binoculars to
view Uranus just one degree above Venus; around January 17th try for Mercury
very low in the Southeastern morning sky.
Join me and the staff at the Challenger Learning Center of Alaska in Kenai for
an astronomy evening on Sunday, December 28th, 7:30pm until 10:00pm. As
Lead Flight Director Tamra Wear organizes this event, Dale Hershberger and I
will bring telescopes and Diana Thomas will inform us about Denai'na mythology
of the starry skies. In case of clouds we'll have a slide presentation.
The center will be open during that time. Contact me or Tamra at
283-2000 for more information.
The Sky in December 2003
The
following description and diagram are applicable all winter in the evening and
throughout the night, from December on well into April. The KPC book
store sells starfinders for $5; check Sky & Telescope and Astronomy
magazines as well.
Find Jupiter in Leo - rising in the East after midnight,
visible in the South until dawn; Saturn in Gemini - rising in the East right
now; Mars in Pisces - high in the South to Southeast right now - then in Aries
and finally Taurus in April, in fact it would join Saturn in May but that's
when we run out of dark skies; Venus on the Western horizon all winter long in
the evening. While stars are fixed relative to each other, you’ll
notice that planets move among the Zodiac constellations.
The dominating constellation is Orion the hunter. It is many
people’s favorite because of its brilliance. Four stars arranged in
a rectangle (with red Betelgeuse, blue Rigel, Bellatrix, and Saiph) outline the
body, while three stars make up the belt with the Orion nebula as the sword
beneath it. Above Orion you find Taurus, part of it in the shape of an
arrowhead including red Aldebaran. And above that are the Pleiades star
cluster, also called the Seven Sisters, a must for binoculars with which you
can see 30 to 50 of its total of 500 stars. To Taurus’ left is the
pentagon Auriga with yellow Capella. Beneath Capella appear Castor and
Pollux, the twins in Gemini, this winter forming a triangle with Saturn. And
then we close this circle towards the horizon, with Procyon and the Number One:
Sirius, the brightest star in the entire sky. Since Jupiter resides
further East, also look for Cancer and Leo, with the former containing the pretty
Beehive star cluster which shows 20 to 30 in binoculars of its total of 350
stars.
Special events in December: the earliest sunset on the 16th, the solstice -
beginning of winter - on the 22nd at 7:04 am , latest sunrise will be on the
27th; this may be startling - and the explanation is too long and winded for
this month's column, thus I refer to the summation page at www.analemma.com.
During Sat/Sun night, on the 13th/14th, look out for the Geminid meteor
shower, one of the three most impressive meteor showers this year.
Finally at the end of the month try to spot Neptune with binoculars just
above Venus while Saturn will be in opposition, i.e. at its brightest and - in
a telescope - at its largest.
Andy Veh
KPC Astronomy Professor
262-0366, aveh@uaa.alaska.edu
The sky in November 2003
Total lunar eclipse
This is a naked eye and/or binocular event.
The total lunar is observable from almost everywhere in the Americas on Saturday evening, November 8. Obviously, this is when we have full Moon which rises when our Sun sets. And lunar and solar eclipses (about 2 or 3 every six months) are the only times when there are any shadows involved.
The total eclipse starts at 1 pm AST when the Western limb of our Moon
touches the most Western edge of Earth's shadow. The decrease in
brightness is so little that only by 3 pm would we be able to notice
something. The total eclipse begins around 4 pm and lasts until
4:30 . Our Moon, very low in the East, is expected to shine then at only
a 1/10,000 of its normal brightness, just a little brighter than Mars which you
find in the Southeast. Also, look out for the Great Square of Pegasus the
eclipsed Moon. Binoculars are the ideal instrument to watch the lunar
eclipse. The eclipse consummates at 6 pm but for all
practical purposes should be over by 5:30 pm.
Unfortunately our Moon doesn't rise until 4:45 pm on the Kenai, so we're seeing
just the latter part of this total lunar eclipse. The Interior can follow
more of the eclipse since they have longer nights and thus the full Moon rises
earlier; the Lower 48 can see most of the eclipse since they're further East
and night starts earlier.
However, even the latter part should be a spectacle as the eclipsed full
Moon is rising over the
Appendix:
Check Fred Espenak's eclipse page at http://sunearth.gsfc.nasa.gov/eclipse/OH/ OH2003.html .
See an explanation for our Moon's phases and you may want to read through this and other trivia. ("Our Moon orbits the Earth and reflects our Sun's light, too. Its phases depend on the angle we view it in relation to our Sun. Our Moon's phases have nothing to do with its own, Earth's, or anybody else's shadow. But eclipses do.")
The Sky in October 2003
The Sky in September 2003
Mars, Uranus and Neptune are the planets this month,
appearing in the South to Southeast in the late evening. I described how
to view Mars' motion across Aquarius and how to find Uranus in last
month’s column and will add about Neptune next month. Also, around
and near September 27, look between 6:30 and 7:30 am during dawn due East to
first find very bright Jupiter very low (beneath bright star Regulus ), then
Mercury even closer to the horizon.
This month I will focus on a special star: Algol, the second
brightest in the constellation Perseus . Many stars are classified as
variables, i.e. varying in brightness. A variation in brightness can be
caused by a star’s intrinsic structure, e.g. it can pulsate. Or it
can be caused by a companion star literally eclipsing it. Actually half
of the stars we see are binary or multiple star systems, whose stars
consequently orbit each other as dictated by the law of gravitation. But
their orbits may be quite tilted with respect to our vantage point in our solar
system; except for a few binary systems like Algol where we see their orbits
almost edge-on. And that's why Algol , the brighter component of such a binary
star system, and its companion regularly eclipse each other.
To first orientate yourself in the starry skies, find the
Big Dipper low in the North; then extend the dipper’s last two stars high
into the North to find Polaris, the North Star, and the Little Dipper; with the
Big Dipper on one side of Polaris, find the constellation Cassiopeia, a nice
sized W, on the other side of Polaris high in the East; from here follow down
towards the Eastern horizon to first find the double cluster in Perseus (great
for binoculars, see chart; finder chart for Algol within the region of Perseus
. [Tilt the chart to the left, so that the W is straight up.]), a medium
sized right triangle, consisting of Algol , Almaak and Mirphak (the latter is
embedded inside quite a few, yet fainter stars) – all three exhibit
almost the same brightness; as a further landmark use Pegasus, the Great Square
to the right (off the chart), also in the East. (If you need a larger
finder chart, you can find one on my web site chinook.kpc.alaska.edu/~ifafv ,
click on “Lecture Notes”, then “The Monthly Sky”.)
Algol and its companion star are in a very tight orbit,
circling each other almost every 3 days (this compares with a 90 day orbit of
our Sun’s most speedy and close companion, the planet Mercury). In
such a tight orbit, the two stars easily eclipse each other: the deeper of the
two eclipses happens when the brighter component, that is Algol , becomes
gradually obscured for about eight hours and its brightness diminishes
appreciably. Algol’s eclipse of its fainter companion a day and a
half later is hardly visible because much less light is masked.
The next times to see these ever-repeating eclipses in
Alaska are Tu /We, Sept. 9/10, from 11pm to 3am; Fr/Sa, Sept. 12/13, 11pm to
3am as well; Mo/ Tu , Sept. 29/30, 12-4am; then We/ Th , Oct. 2/3, 10pm-6am;
Su/Mo, Oct. 5/6, 10pm-2am. Algol is usually of almost the same brightness
as Mirphak and Almaak , the other two stars in this right triangle, are.
But during eclipse it fades to the same faintness as the star just below, boxed
in in the diagram. During the five nights just listed, Algol would fade,
brighten, fade, fade and brighten, brighten, respectively.
Another eclipsing binary star is Sheliak, the second
brightest star in the constellation Lyra, next to very bright Vega, high in the
fall sky. Algol has the largest change of brightness, thus it is the one
described here at length.
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Above left: finder chart for Algol within the region of
Perseus . [Tilt the chart to the left, so that the W is straight up.]
Above right: how stars can eclipse each other, with data of Algol's brightness
variations during an eclipse.
Below: a large sky finder chart (see text for September).
The Sky in August 2003
Now that
summer makes way for some more night hours, hopefully cloudless, I’m able
to resume my astronomy column. Don’t misunderstand me: I love
The astronomy season starts out with a Bang as the first major planet will be
Mars at its Best. It’ll be joined by Saturn, Venus and Jupiter
later this year, and there will be a lunar eclipse on November 9, but for now
it’s Mars.
The red planet has been an odd-year planet throughout the 90s and 00s, i.e. it
became last prominent in 2001, then now obviously, and next time in late
2005. Mars needs about 1 year and 11 months for one orbit. So as
Earth orbits our Sun and is back at the same spot after exactly one year, Mars
is almost on the other side of our Sun. As we’re trying to catch up
during our second orbit, Mars makes the feeble attempt to elude us, but finally
we’ve caught up and get closest to Mars once again after 2 years and 2
months. Hence the two year recurrence of Mars from our vantage point.
As for late 2003 and early 2004 Mars has been moving and retrograding across
Aquarius 1 since June
[retrograde motion started in early August] through November [retrograde until
late September], Pisces in Dec. & Jan., Aries in Feb., Taurus in March
& April. As Mars will enter Gemini in May of next year, Earth and
Mars will be in disparate parts 2
of their orbits.
We like to be close to Mars to observe it because we can only see it when both
of us are on the same side of our Sun, else our Sun would be in between,
rendering Mars obliterated by the bright daytime skies, as will be the case for
the remainder of 2004. But we also like to be closer to a planet because
it appears brighter and bigger, which is especially the case for Mars.
And this year is extra special because two events coincide: Mars’ closest
approach to our Sun [called perihelion] on its elliptical orbit on Aug. 30 and
Mars being in opposition with respect to Earth, i.e. Sun on one side from us,
Mars on the other, on August 28, making it – at 35 million miles –
our closest encounter in recorded history, in fact since our Neanderthal
cousins saw it in 57,617 BC yet closer. Although that’s a record
and there’ll be some media hype about it, the main event is to enjoy
observing Mars. In other words, don’t wait until August 28, 2287 ,
when it’ll be still closer, brighter and bigger, but enjoy it now, in two
years, in four, in six. (See the June 2003 issues of Sky & Telescope
and August 2003 of Astronomy; available at several libraries and stores on the Kenai.)
You can’t miss reddish Mars because it’s be the brightest object in
the night time sky, apart from our Moon if that is out. The diagram shows
the positions of Mars during August and September around midnight . View
Mars due South about 15 degrees above the horizon, either above the
There are some bright stars out but none of them is nearly as bright as Mars,
though they could be more prominent if Mars is lost in some haze on the
horizon. These stars are reddish Arcturus and Antares in the West and
Southwest (these are huge, though cool [radiating at around 5000 F which
corresponds to red] dying stars called Red Giants, unlike Mars which gets its
color from its oxidized, rusted surface rocks) while Mars is in the East or
South, depending on the time of night. Other bright stars make up the
summer triangle overhead, Vega, Deneb and Altair .
I just don’t have the space here to rattle off facts about Mars, but you
can look up a lot about Mars in plenty of good books on the solar system (there
are good juvenile books too). However, if you own a telescope or if you
like to join me some evening (send me an e-mail or call me at KPC), you will see
a reddish, yet small disk [it’s still tiny in most amateur telescopes, so
don’t expect too much] and with some patience you might see a polar cap
or two and contrast bright and dark regions on Mars’ surface (see
Astronomy August 2003, p.82).
Interesting dates are also August 12 and September 8 when Mars and Moon will
appear close to each other and September 24 when Mars leads the way to
Uranus. How to find Uranus: first of all binoculars are advised.
Aquarius doesn’t have any bright stars – but Mars really
helps. See if you can recognize the faint stars that make up
Aquarius. Then use binoculars to go from Mars to the star iota Aquarii on
its upper right. Now you should have in your binoculars the same view as
depicted in the inset. Use iota and the triangle 39, 42, and 45 as a
recognizable pattern. There will be two objects of similar brightness
above the triangle: the star e Aqu and the planet Uranus. Come back a
week later and you’ll notice that Uranus will have retrograded to the
right.
And since I mentioned the word retrograde a few times: Mars, Earth and all
other planets orbit our Sun counter-clockwise, each at its own fairly steady
rate, always in the same direction. But as we’re speeding past Mars
and other outer planets, it looks or appears as if Mars is going backwards
(retrograde), but only because we’re changing our vantage point in space
so rapidly.
Andy Veh
KPC Physics and Astronomy Professor
aveh@uaa.alaska.edu
262-0366
1 Aquarius is my
sign since I was born in February. Our birthdays are linked to those
originally astrological and astronomical signs because that’s where our
Sun appears in on one’s birthday. Thus we also can’t see our
own sign on our birthday because that’s where our Sun is. But a
Zodiac constellation becomes visible about half a year away from the assigned
month because now our Sun is in the opposite part of the sky. Hence
Aquarius (February) is visible during summer while Taurus (May) is a winter
constellation.
2 This is called a
superior conjunction. The word opposition is actually reserved for the
situation when Sun & Mars are opposite each other with respect to Earth
.
The Sky in May 2003
I recognize that now in
1. A Mercury transit: only the two inner planets, Mercury and Venus, can get
between us and our Sun. Because their orbits are tilted - and despite the
fact that they only need 88 days and 225 days, respectively - such so-called
transits are rare (because usually they orbit too high or too low): at least
Mercury transits every seven years on the average but Venus only twice every
130 years or so. Luckily for me, the latter will transit soon on June 8,
2004 as seen from Europe (it's worth a travel for me), Asia and Africa, and
then in 2012 as seen from Alaska, Yukon, East Asia and Australia; after its
last two transits occured during Grant's and Arthur's tenures in the White
House. But back to Mercury: as seen from all of Asia, Europe, Africa and
partially (during sunset or sunrise) in
2. A lunar eclipse: our Moon's orbit is tilted as well and thus eclipses don't
happen every month. But every half year they do occur - in pairs of lunar
and solar eclipses. In the evening hours of May 15, our Moon in its full
phase (only then can a lunar eclipse happen) enters the Earth's shadow -
visible from all of South America and the Eastern part of North America and
partially visible (during sunset or sunrise) from Europe, Africa and the
Western part of North America, even in Southeast Alaska. The next lunar
eclipse visible from
3. A solar eclipse: On May 30/31 an annular solar eclipse happens as our Moon
crosses exactly between Earth and Sun. However, our Moon is at its
farthest distance in its orbit, thus appears smaller and therefore produces a
ring of our Sun around it during the eclipse (called annular). Best
places for the eclipse are
Also, check the May issues of Astronomy and Sky & Telescope.
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The Sky in April 2003
The planets this month are still Saturn and Jupiter, the latter dominant in the
Southern sky, the former being close to Western horizon. The first quarter
moon will be near Saturn on the 7th, assisting in finding the ringed
planet. Those rings are at their widest since 1987, having opened up for
a grand view; Saturn is also at its closest to our Sun during its 29 year
orbit, making it extra large in a telescope or good binoculars (mount them on a
tripod or hold them very steady with your elbows on a car’s roof); and
while you’re at it, look for Jupiter’s moons as well.
The great constellations and stars of winter, from Orion to
Taurus and Gemini, encompassing Jupiter and Saturn, are now quickly setting in
the West. But look for Orion and the sky’s brightest star, Sirius,
on the Southwest horizon.
Noteworthy among the spring constellations is especially Leo
the lion, which follows Cancer where Jupiter resides and through which it moves
this year (still close to the Beehive cluster). Spring is here as Leo
appears high in the South.
Venus is now very low in the East during dawn while Mars
becomes more of a very late night object (it rises after 3 am ). Despite
it being so low, Venus is still easy to spot because it's so bright. Mars
is of course red, the brightest object in its part of the sky (near Capricorn
low in Southeast during the wee hours) and is joined by our third quarter Moon
around the 23rd.
But this month’s favorite planet is actually the most
elusive one. April is the only month this year to spot all five naked-eye
planets within the same night as Mercury reaches its greatest elongation from
our Sun on the 16th. On that evening it is trailing our Sun by a full 20
degrees in the West during dusk. One might want to enlist the help of the
stars in Taurus, Saturn, and the Pleiades and connect from there to the Western
horizon where Mercury is the only bright object. A telescope shows half
of Mercury illuminated (a "first-quarter" inner planet at that time)
because at greatest elongation Mercury, Sun, and Earth make up a right triangle
which allows only half of Mercury's Earth-viewed side to reflect sunlight to Earth.
To top off Mercury’s great showing, it would have gotten even better: the
speedy planet transits across our Sun’s disk on May 7 – a great
event if you were in Asia , Africa or
I will set up my telescope(s) on the Kenai Beach Access
parking lot (end of Spruce Dr) on Friday, April 18, around 10 pm for a public
evening – weather permitting (otherwise on April 19, then 20).
With a little luck one can find Mercury very low in the West
on April 2nd (or even on the 3rd) when it is joined by our Moon’s
sliver.
The Sky in March 2003
The
planets this month are still Saturn and Jupiter, the latter being the brightest
object in the evening sky, high in the South. Saturn is 40 to 50 degrees
to the West of Jupiter, somewhat fainter and appearing yellow-red beneath the
pentagon-shaped constellation Auriga. Further west yet, by another 30
degrees, are the Pleiades, also called the Seven Sisters, a beautiful open star
cluster. (10 degrees is the equivalent to a fist held at arm’s
length.) The first quarter Moon will be near the Pleiades on March 9,
near Saturn on March 10&11, and near Jupiter on March 14.
All around Jupiter and Saturn are still the great constellations and stars of
winter, from Orion to Taurus and Gemini.
However, the spring constellations are quickly moving in and out of view.
Most prominent among them is Leo the lion, which follows Cancer where Jupiter
resides and moves through this year. Seeing Leo in the East means that
spring will be here soon. But because nights are getting rather short,
we’ll see it only until early May.
Venus is now getting lower in the Southeast during dawn. It’s
almost easier now to see the much fainter reddish Mars in the Southeast,
passing near the red giant star Antares (in Scorpius) and through Sagittarius.
This is also the month of the Messier Marathon named after Charles Messier, a
French comet hunter of the 18th century. As he looked at fuzzy comets, he
noticed that some of the objects aren’t moving – and correctly
concluded that they’re not comets (which orbit our Sun and thus
move). So he started a list of all those fuzzy, not-moving objects, from
M1 to M110, with the single objective of telling fellow comet hunters:
“Hey buddy (‘ allo copain ’ in French), don’t look at
these – boring.” Well, as it turns out, these are great deep
sky objects. The term “deep sky” makes sense because the closest
ones are already a few hundred lightyears away, e.g. the open clusters M45
Pleiades and M44 Beehive (see the chart for how they look like in binoculars),
the star nursery M42 Orion Nebula, and the planetary nebula M57 Ring Nebula;
some of the ones at a few thousands of lightyears away are the Supernova
remnant M1 Crab Nebula, the globular (dense) star cluster M13 Hercules cluster;
and some of them are millions of lightyears away, M31 Andromeda Galaxy,
M104 Sombrero Galaxy. All in all, the list contains lots of exciting
objects to look at that are in fact visible with a good telescope under a dark
sky. And they have a shape which makes them extra pretty (that’s how the
Sombrero Galaxy got its name). For astronomers, March means Madness, as
we’re able to see all those in a single night. A great web site with
photos is www.seds.org/messier/ .
Very good to excellent for binoculars are M13, M31, M42, M44, M45, M24 (a dense
region of the Milky Way in Sagittarius).
Once again, I like to refer to Astronomy and Sky & Telescope magazines at
libraries and stores, star finders (about $5 at the KPC bookstore and at River
City Books), and star charts on the internet (e.g. skyandtelescope.com/observing/skychart
). Those charts are much better than anything I can reproduce and show
exactly where those Messier objects are.
The Sky in February 2003
In this month’s column I’m listing a few internet resources,
especially useful for observations before the winter is over and before the
nights become too short.
The best interactive star charts I have seen are at skyandtelescope.com/observing/skychart
(type in your latitude and longitude, 60N and 150W for the
To observe satellites go to heavens-above.com
, which features the ISS (International Space Station), Iridium flares
(satellites owned by the cell phone company of the same name), and Hubble Space
Telescope, plus many others. Iridium flares can be quite spectacular as
these satellites reflect our Sun’s light very effectively and thus
brighten enormously for a few seconds.
To follow the trajectories on your computer screen of some of the same
astronomical space telescopes (HST, Chandra [X-ray observatory], COBE [Cosmic
Background Explorer], UARS [Upper Atmosphere Research Satellite]), the ISS, and
a space shuttle when it’s space borne, go to liftoff.msfc.nasa.gov/RealTime/JTrack/Spacecraft.html
(a search for “jtrack ” on google.com is quicker). Most
satellites are in low orbit and thus enter Earth’s shadow readily.
Look for satellites up to two hours after dusk and before dawn.
spaceweather.com
tells you about current solar activity, aurorae , meteor showers in a non-scientific
jargon and newspaper style. I use this as my home page in MS
Explorer. They also post amateur photos of interesting sunsets, aurora
displays, meteor showers. For good seeing conditions check the Weather
Channel’s weather.com
, wunderground.com
and the Clarion.
>How does our Sun look today? Check sohowww.nascom.nasa.gov
for visible light, ultraviolet, magnetic and corona images. I have their
screensaver permanently on my computer. It shows images that are just a
few hours old. Once in a while one sees a planet go by, a comet plunging
into our Sun (showing as short streaks compared to point like stars), and Comet
Kudo-Fujikawa just flew by at the end of January. Looking at our Sun on a
computer screen is the only safe method I can advise without damaging
one’s eyesight (but I will expand on safe observations during my May
article which will feature the May 30/31 partial eclipse).
For the latest Hubble Space Telescope (HST) images check www.stsci.edu
. Due to newly developed adaptive optics techniques, ground based
telescopes such as Keck (search for keck on Google ), and Subaru at naoj.org ,
rival HST’s images.
To be prepared for the next show of the aurora borealis, subscribe to Charles
Deehr’s UAF listserv via gi.alaska.edu
. It features a daily map of
All of these listed here are really user friendly. It’s easy
to find what you’re looking for and easy to figure out where to enter
variables such as one’s location. I can also send you these via
e-mail, and you can simply copy the web addresses.
The sights in the sky are really similar to last month’s, thus I’m
reproducing the same image here. But as I said, magazines really feature
the best charts.
And yes, for the umpteenth time, the very, very, very bright light in the
morning in the Southeast is indeed Venus. But did you notice red Mars
close by? Jupiter in the West? Jupiter and Saturn in the
evening’s eastern sky?
Also, the zodiacal light is visible during the last two weeks of
February. A short explanation can be found at the “Earth &
Sky” radio show’s earthsky.com/2000/es000327.html
.
The Sky in January 2003
One could
just say that it’s warm and thus summer when we’re close to our Sun
and cold and thus winter when we’re far away. However, that cannot
be correct because we have our closest approach to our Sun at 91.4 million
miles this January 3 and are farthest at 94.5 million miles on July 3 or 4 (the
average distance being 93.1 million miles). Also, the Northern and
Southern hemispheres have opposite seasons, i.e. Australia has summer right
now.
Instead, seasons must be explained differently: it’s
the tilt of Earth’s axis that produces them; not because we like that
theory, but because it delivers the correct explanation. And, taking it
to the extreme in
To understand seasons best, model the seasons by using an
Earth globe, a bright lamp. Position the globe about three feet from the
lamp, so that the Northern part of the axis is tilted towards the lamp and also
points at a corner in your room. The corner shall substitute for the
North star . Notice that our Sun shines more directly onto the Northern
hemisphere and that we get long days, i.e. it’s summer. Now make
the Earth orbit our Sun with the axis pointing at the corner all the while
keeping a distance of about three feet turning the lamp so it keeps shining on
Earth. On the opposite side, the Earth’s axis is now pointing away
from our Sun. We get sunlight under a much more shallow angle (which
produces a lower arc) and days are short, i.e. it’s winter. Notice
that the Southern hemisphere gets more direct Sun and longer days, thus
it’s summer for them. Fall and spring are in between these
extremes. Check out my seasons lecture at
http://www.wncc.net/courses/aveh/lecture/lecmove.htm#Seasons
The following description and diagram are applicable
all winter in the evening and throughout the night, from December on and even
into April; this is an excerpt from an article I wrote for the Homer
News’ Holiday Delights issue last month.
Find JUPITER in Cancer and SATURN between Gemini and
Taurus. While stars are fixed relative to each, you’ll notice that
planets move.
The dominating constellation is Orion, the Hunter. It is
many people’s favorite because of its brilliance. Four stars
arranged in a rectangle (with red BETELGEUSE, blue RIGEL, BELLATRIX, and Saiph)
outline the body, while three stars make up the belt with the Orion nebula as
the sword beneath it. Above Orion you find Taurus, part of it in the
shape of an arrowhead including red ALDEBARAN. And above that are the
Pleiades or Seven Sisters, a must for binoculars. To Taurus’ left
is the pentagon Auriga with yellow CAPELLA. Beneath Capella appear CASTOR
and POLLUX, the twins in Gemini. And then we close this circle towards the
horizon, with PROCYON and the Number One: SIRIUS, the brightest star in the
entire sky. Since Jupiter resides further East , also look for Cancer and
Leo. (The KPC book store sells starfinders for $5.)
As for the morning sky, you can’t miss bright Venus above the Southeastern
horizon in the pre-dawn sky and reddish, but much fainter Mars close by.
While Venus will vanish into the dawn sky by February, Mars will get ever
better this year, appearing in the morning during winter and spring, and in the
evening during fall and next winter. Notice that bright Jupiter appears
in the morning above the Western horizon.
Homer News’ Winter Bulletin 2002/03
(The following descriptions and diagrams are
applicable to any location.)
It’s cold outside, but the nights are long and the
hardy astronomer is dressed warm and in layers and enjoys a sky filled with 9
of the 25 brightest stars. I love this winter sky. The view is due East
in the late evening, over the Kenai mountains, or South later during the night,
respectively later in winter. Note that the following descriptions and
the diagrams are applicable all winter, from December on and even into April.
Actually, before you’re able to decipher the stars of winter, you will
notice two bright giant planets among them: JUPITER in Cancer and SATURN
between Gemini and Taurus. While stars are fixed relative to each,
planets move: the Greek word planet means wanderer or hiker. You can
nicely see that as Jupiter retrogrades East-West in Cancer and Saturn from
Gemini back into Taurus. As planets orbit around our Sun, and from our
vantage point on Earth seemingly through the Zodiac constellations, they
actually do so West to East. But when we pass them, during those months
we can see a planet almost all night, they seem to move East-West, retrograde,
until we have passed them completely. They really orbit on an ellipse in
the same direction all the time but because we ourselves are orbiting, they
seem to retrograde as seen from Earth. With good binoculars held steady
or with a good telescope (make sure you get one with good optics and stable
tripod) you should see Saturn’s rings and Jupiter’s four large
moons and perhaps even Jupiter’s cloud bands.
The dominating constellation is Orion, the Hunter. It is
many people’s favorite because of its brilliance. Four stars
arranged in a rectangle (with red BETELGEUSE, blue RIGEL, BELLATRIX, and Saiph)
outline the body, while three stars make up the belt with the Orion nebula as
the sword beneath it. Above Orion you find Taurus, part of it in the
shape of an arrowhead including red ALDEBARAN. And above that are the
Pleiades or Seven Sisters, a must for binoculars. To Taurus’ left
is the pentagon Auriga with yellow CAPELLA. Beneath Capella appear CASTOR
and POLLUX, the twins in Gemini. And then we close this circle towards the
horizon, with PROCYON and the Number One: SIRIUS, the brightest star in the
entire sky. Since Jupiter resides further East , also look for Cancer and
Leo.
The evening diagram shows only a small part of the sky, but
I picked, in my opinion, the most interesting part. However, there is
more in the sky: the huge summer triangle is called that way because it’s
the dominant feature in the summer sky but is still visible until January in
the West. It is comprised of VEGA, DENEB and ALTAIR, another three of the
brightest stars. Since these three stars are from different
constellations (Lyra, Cygnus,
How do you find the North star Polaris? Take the last two stars of the
Big Dipper’s pan and mark off a distance five times their separation,
towards North. You’ll always end up at Polaris which is the last
star of the smaller and fainter Little Dipper. Since the Little
Dipper’s stars are fainter, you might need to be in a darker area without
light pollution. You can also depict the two dippers as if you were
flipping pancakes forth and back between the two. Polaris is only 49th in
brightness and thus appears way fainter then most people expect: its claim to
fame is its fixed position of 60 degrees (marking one’s latitude) above
the Northern horizon, not its brightness.
Star finders, star charts and my diagrams are somewhat
deceiving as it is hard to depict the true brightness of stars on a sheet of
paper. However, these should be easy: Big and Little Dipper, Summer
Triangle, Orion, Auriga, somewhat Taurus, even perhaps Leo. A little
harder should be Gemini and Cancer. And I didn’t even mention Canis
Minor and Major in which Procyon and Sirius reside; the former doesn’t
look like a little dog at all, the latter is too low on the horizon when seen
from the Kenai.
Other interesting features to look for are the Pleiades and
the Hyades, two open star clusters in Taurus, the Beehive, a pretty globular
cluster in Cancer, and various globular clusters in Auriga. All of these
are gems for binoculars.
Mercury’s best showing is in April during dusk. On April 2,
it’s just to the right of our Moon’s thin sickle. During mid
April it will appear about 10-15 degrees above the WNW horizon, 50 minutes
after sunset; but it’s hard to identify it since there is no guide star
next to it.
The other two bright planets appear in the morning
sky. Since sunrise occurs Venus rises so late in the
morning, everyone should be able to see them, even night owls like me.
Venus, the brightest object in the sky aside from Sun and Moon, dazzles in the
East before sunrise. During December and January Venus and the reddish,
fainter Mars are dancing close together, first near SPICA in Virgo, then near
red ANTARES (translated from Arabic as “the rival of Mars”) in
Scorpius. Throughout February they separate from each other. Come
March it’ll be harder to find Venus. But Mars will climb more and
more in the early morning sky.
For more comprehensive descriptions and especially star charts see the two most
popular monthly publications, Sky & Telescope and Astronomy.
They’re sold in various stores and are available in some public
libraries, e.g. in Homer and Kenai. The January issue of S&T contains
the “ Skygazer’s Almanac 2003” and both magazines issue
Skywatch ’03 and Explore the Universe 2003, also available right now in
stores. Their web addresses are skypub.com and astronomy.com. The
former also features one of the best interactive star charts I have seen, at
http://skyandtelescope.com/observing/skychart / ; another good one is at
http://www.astro.wisc.edu/~dolan/constellations/java/Leo.html . An
indispensable aid is a star finder, also called planisphere or star and planet
locator. It’s two large pieces of cardboard fitted into each other,
so that one can arrange them to find all stars during the entire year, at all
dates and times, every year. It costs between $3 and $10 and should be
available at novelty, science, and perhaps toy stores. As for books, my
friend Doug Rice, Astronomy and Spanish professor in
Andy Veh
KPC Physics and Astronomy Professor, Soldotna
aveh@uaa.alaska.edu
(907) 262-0366
The Sky in December 2002
Christmas is upon us and your
best astronomy buy is … a starfinder which costs between $3 and
$10. I didn’t see any at local stores but you can e-mail me at
aveh@uaa.alaska.edu and I can tell you where to order one. Some novelty
and nature or science stores in
Venus is the bright object in the East pre-dawn sky. Our Moon will be
full on December 19. Mars is low in the Southeast before sunrise.
Another very bright planet will join Saturn in the evening sky this month:
giant Jupiter. The accompanying diagram would help you find Jupiter above
the Eastern horizon after 10 pm early this month and 8 pm late this
month. But Jupiter is way brighter than all stars around it, so that you
actually can use it to find the constellations of Cancer and Leo. Use
binoculars to look for Jupiter's moons. And again look for Saturn: from
Cancer and Leo go West to Gemini and Taurus. In the Southeast
you’ll find the constellation Orion, the star cluster Pleiades (Seven
Sisters, right from Saturn), and many bright stars: Sirius, Procyon, Aldebaran,
Castor, Pollux, Capella … check your newly acquired starfinder. On
the back it usually lists the planet positions for the next four years.
Also see last month’s diagram or check out Astronomy and Sky &
Telescope magazines at the Kenai library and at various stores (I’ve seen
them at Fred Meyers and at Carrs).
Some people may also be lured by department store telescopes (they waste about
$100) which advertise as 420x magnification and come with flashy pictures of
Saturn and comets. I call them attic-dust-collectors. Well, you can
actually use them for looking at our Moon or see Jupiter’s moons
(appearing as dots). But binoculars would be just as good for that. I
know , this is a really tempting gift to present to a youngster. But,
please, please, please, don’t do it! I say this for selfish
reasons, (a) I want people to enjoy astronomy, (b) I don’t want anybody
to get frustrated by a wobbly telescope that produces blurry images, and (c) if
you keep enjoying astronomy you might even take my class.
Two things you have to look for when you want to buy a telescope: a stable
mount for the telescope and that the finder scope is aligned with the telescope.
My advice: buy a starfinder, stay with the binoculars that you perhaps already
own. And if you really want a good telescope, call me at 262-0366 for
advice, stop by my KPC office to pick up an Orion catalog of which I have
plenty (or order one through www.telescope.com).
This month also marks several benchmarks for daylight: the earliest sunset
occurs at 15:53 on 12-15, the latest sunrise at 10:14 on 12-27. These
slight differences are due to Earth’s tilt of axis, which makes a
day/night cycle an average 24 hours, and the exact day depends on latitude. I
will explain the exact reasons in an upcoming column. But, as expected,
the shortest day lasting 5 hours and 41 minutes is on the winter solstice on
12-21. On that day our Sun will ascend to a whopping 7 degrees (90 minus
latitude of 60 minus axis tilt of 23 on the winter solstice) above the Southern
horizon at local noon, around 1 pm (because we're so far west in our Alaska
time zone, local noon occurs an hour later than it does in Southeast).
Then, on January 3 we will have our closest approach to our Sun at 91.6 million
miles, compared to an average 93.1 million miles.
The Sky in November 2002
Perhaps you’ve seen Scott Moon’s aurora photo published last
month. Or look at mine here. Or try to take one of an aurora, of
constellations or a meteor shower yourself.
With just three pieces of equipment – a Single-Lens-Reflex camera with a
“B”-bulb setting, a cable release (costs about $15 at a camera
store) and a tripod – everybody can take such photos. Here’s
how to do it.
First, any type of light pollution messes up the exposure. Take
time-exposures outside of town, the darker the area, the better, e.g. the
turn-outs on
The longer an exposure, the brighter stars become and more fainter ones appear:
as a rule of thumb divide 1000 by focal length, e.g. 1000/50 equals 20
seconds. You can or perhaps should take longer exposures for meteor
showers and aurorae – but notice that star trails will show up (stars seem
to move because we’re rotating). Start the exposure by pressing the
cable’s button, tighten the screw, count the seconds, then stop the
exposure by loosening the screw. Next picture.
(Log on to my home page http://chinook.kpc.alaska.edu/~ifafv/ and access my
astrophotography lecture for more details. I will also offer a non-credit
class on the topic in January.)
This month’s Leonid meteor shower will peak around 1:30 AST, the night of
Mo/ Tu, Nov. 18/19. Its radiant is in the constellation of Leo on the SE
horizon: as Earth orbits our Sun through space, we’re crossing the orbit
of comet Temple-Tuttle (as we’re “heading towards” Leo) which
leaves debris in the form of dust and grains behind and those are the particles
that burn up in our atmosphere, creating meteors that seem to streak away from
Leo, i.e. they emerge from the SE. It’s easy to find Leo, since the
Lion seems to swallow bright Jupiter. The Leonids have been in the press
during the past few years as they’re really good only every 33 years and
this is the last good year.
(Log on to skypub.com, astronomy.com or check out the newest issues of these
monthly magazines, Sky & Telescope” and “Astronomy”, at
your local library; e.g. the Kenai Public Library carries them.)
This month Saturn is the first bright planet to emerge in the evening.
Find it using the accompanying diagram of the constellation Taurus on the E
horizon, part of which looks like an arrow head or the snout of a bull, while
two more stars to the left make up the horns of the bull. If you have a
telescope, you should be able to see the rings. (If you don’t have
one, please consult me for advice on which one you may want to buy;
aveh@uaa.alaska.edu.) Using binoculars check out the star clusters of the
Pleiades and the Hyades (the arrow head next to the Red Giant star Aldebaran).
The Sky in October 2002
I’ve just moved here, so
what would I know about the night skies on the Kenai? Well, fortunately
the movements of planets, Sun and Moon and the rotation of Earth –
yielding the stars’ daily apparent motion – are very predictable,
so here we go.
The North Star is higher than what I’m used to, at about 60 degrees above
the Northern – where else – horizon. Don’t look for a
bright star, in fact it’s only the 49th brightest star as seen from our solar
system. Instead, find the Big Dipper first, fairly low in the Northwest
in the early evening, then put two fingers on the last two stars in the
Dipper’s pan and finally mark that distance five times up: you’ve
found the North Star. If you’re out of town, you will also be able
to find the Little Dipper, of which Polaris is at the end of its handle.
Another hint: it’s as if you were flipping pancakes back and forth
between the two dippers.
On the other side of Polaris you’ll find Cassiopeia in the shape of a W,
fairly high in the Northwest. From Cassiopeia on you see a faint band of
many stars extending high through the Eastern sky and ending on the Southern
horizon: the Milky Way, i.e. the galaxy in which we reside.
As you follow the Milky Way’s span, you also notice three bright stars
high in the Southern sky: those are Vega, Deneb and Altair , which make up the
summer triangle.
When you look at the Southern horizon you should see some Zodiac constellations
such as Scorpius and Sagittarius – but you don’t because
we’re so far North . Thus they just graze the horizon, and since
our Sun will reside in these constellations in the winter, it will soon also
just graze the horizon.
There really is only one planet available this month. It’s a
fainter one, but it’s possible to see it with binoculars: Uranus, the
first planet that was really discovered (Mercury, Venus, Mars, Jupiter and
Saturn are so bright that they have always been known to mankind).
Start out by looking towards the horizon just East of South: find an elongated
triangle (see diagram) of stars; these are Nu Aquarii and Alpha and Beta
Capricorni . You’ll notice that you’ve got the right ones
when using your binoculars: the upper right one (Alpha Cap.) is actually a multiple.
Next go down and you find a pretty triple. Then go left (you may do this
without your binoculars) and you see four stars in line. Above the
furthest left are three stars - use binoculars again.
The lower of these three is named “Kate”, for my wife.
I’m kidding, but I did make her a nice chart of Capricornus , attached a
photo that I took and framed it (cost: five bucks). That method sure
beats the fifty Dollars some phony companies charge. After all, the only
one recognizing the star named in her honor is me: if you “buy” a
star, no astronomer and no astronomy organization will recognize it because it
would be way too cumbersome and completely unnecessary for us to make catalogs
of names for millions of stars. However, the 10,000+ known asteroids are
officially named after people, Paul, George, John, and Ringo among them - but
you get to choose a name only if you’re the discoverer.
Anyway, look to the left of “Kate” and you see two lights: one is a
star, the other, perhaps exposing some greenish hue, is Uranus. How do we
know? Because I told you and you see it in the diagram! But seriously,
astronomy is a science and anybody can be a scientist and find out for himself:
Uranus moves across the sky - that's how we know. Mark its position on
the night you found it, then look at it a week later and Uranus will have moved
slightly. If you try to extend your expertise, find
Andy Veh
KPC Physics and Astronomy Instructor
ifafv@uaa.alaska.edu
http://chinook.alaska.edu/~ifafv
The Sky in June 2002
The big event in the late afternoon on Monday, June 10, is a partial solar
eclipse visible for the western portion of
This means that our Moon will obscure up to 20% of our Sun, from 3:30
pm to 5:20 pm , as seen from
A short synopsis (too short unfortunately) of eclipses:
We have a new moon and a full moon every month (the exact number is 29.5 days),
i.e. that's also when Sun-Moon-Earth are "aligned", the main
condition for an eclipse. But alas, the plane of our Moon's orbit is
tilted with respect to the Earth's orbital plane (by 5 degrees). This
means that during new or full moon our Moon usually orbits too "high"
or too "low". But to do so, our Moon must also cross the
Earth's orbital plane twice each month, and every six months these two
crossings are precisely between Sun and Earth (Solar eclipse) and "behind"
Earth (Lunar eclipse).
Even though a solar eclipse occurs twice a year somewhere on Earth, it's still
a rare event. Our Moon is small compared to Earth. Therefore the shadow
of our Moon covers only a small path on Earth: the next total solar eclipse in
North America will be on August 21, 2017. In the mean time we
either have to travel (I'm looking at Turkey in 2006 and China in 2009) or we
can stay put and enjoy the next partial solar eclipse: May 2012. (Lunar
eclipses can be seen more frequently, the next two visible from the Northwest
occur in November of this year and in May next year.)
If you want to know more about eclipses, search for "Fred Espenak" (he's NASA's eclipse guru) on google.com (his June 2001 eclipse photo appears on the June cover of Sky & Telescope). On my web site, http://www.wncc.net/courses/aveh/lecture/ lecmove.htm , are some eclipse animations.
Another interesting event occurs in late May and early June when Venus and Jupiter appear right next to each other in the Western sky during dusk. Please tell friends not to report UFOs: these are our two brightest planets.
Andreas Veh
BMCC Astronomy Instructor
|
The grey dot and arrow depict the path of greatest eclipse (during this eclipse it's annular, that is in the form of a ring). |
Sun during maximum eclipse (using a proper solar filter).
Only a proper commercially sold solar filter can be used with a telescope. Improper use will cause blindness! |
Doug Rice and I will set up telescopes with
proper solar filters in the library and city hall parking lot on Dorion in
Pendleton. We will give people a safe look at the solar eclipse.
(This means that our Moon will obscure up to 40%
of our Sun, from 5:00 pm to 7:00 pm , as seen from
BMCC Physics Instructor
The Sky in April and May 2002
Once
again the planets align. And once again it’s hyped as a
“rare” event. Of course, I have to admit that it is really
interesting that all five naked-eye planets – Mercury, Venus, Mars,
Saturn, Jupiter – can be seen close together for the first time
since 1980. However, planetary alignments are rather frequent [in
over-hyped press announcements the word "rare" is used too freely],
e.g. there was one in May 2000, but they were obstructed by our Sun's glare,
and one in fall 1998, albeit without Mars.)
Anyway, the spectacle goes on during the entire month of April and culminates
from May 3 to 10. One starts looking during twilight: an ultra-bright
Venus appears in the West, with rust-colored Mars to its upper left, yellowish
Saturn even higher (between red Aldebaran and Pleiades). During the next
weeks, both Mars and Venus are crouching in on Saturn, finally Mercury joins
the scene. All the while bright Jupiter stoically hovers above those
four.
Another way of finding the planets is to extend an imaginary line from just
North of West high into the Southwest (the path our Sun took during the late
afternoon, also called the ecliptic): all five planets can be found along the
ecliptic.
With good and stable binoculars one could see Jupiter’s moons and perhaps
Saturn’s rings.
Interesting is also that the bright stars of winter are close by: the brightest
star Sirius low in the Southwest, furthermore the constellations of Orion with
red Betelgeuse and blue Rigel, Gemini (where one finds Jupiter), Taurus (where
Saturn and Mars are right now), then Procyon between Sirius and Jupiter and
yellow Capella high in the West. However, these winter stars will be gone
pretty soon.
Subject: Check this out...once in a century chance to see this!
Message no. 75: Posted by Danielle Daugherty ( daughert ), Tue Apr 02, 2002
11:55
"Several planets are assembling toward a rare alignment later this month,
when five of them will crowd into a patch of sky small enough that all will be
visible in a single glance. The setup will provide a planet-watching
opportunity that won't be repeated for a century.
The most compact gathering of Venus, Mars and Saturn that will be visible
in the western evening sky from May 3-10 this year is just one of only five
such planet trios easily visible in a dark sky between the years1980 and 2050.
The best view, he says, will be during the evenings of May 5th and 6th, when
these three planets form an eye-catching compact triangle."
Check out this site…there is much detailed information about all of
this!!!!
http://www.space.com/scienceastronomy/solarsystem/planets_align_020402-1.html
Andreas Veh:
I agree it's kind of cool. (But it doesn't have anything to do with
people getting hyped about dooms day or something. Planetary alignments
are rather frequent [in over-hyped press announcements the word
"rare" is used too freely], e.g. there was one in May 2000, but they
were obstructed by our Sun's glare, and one in fall 1998, albeit without Mars.)
Anyway, since you take this astronomy class,
you know where the planets are (I noticed ultrabright Venus last evening in the
West) , you can see how it develops: Mars to Venus' upper left, Saturn even
higher (between Aldebaran and Pleiades). Then (from now until early May)
both Mars and Venus are crouching in on Saturn, finally Mercury joins the scene
while bright Jupiter stoically hovers above those four.
The
Sky in March 2002
All around Jupiter and Saturn are still the great
constellations and stars of winter, from Orion to Taurus and Gemini. To find
these more easily, pick up Astronomy or Sky & Telescope magazine from a
library (e.g. at BMCC), or buy a star finder for about $5 at a bookstore (e.g.
at BMCC), or find a star chart on the internet. One of the best is at http://skyandtelescope.com/ , click on
Observing, Sky Chart.
Towards the end of the month look out for bright Venus above the Western
horizon during dusk.
A nice bonus this month on the 18th and 19 th is the close approach of the asteroid Vesta to Saturn and its moons. The accompanying chart shows an inverted view as many astronomical telescopes provide it.
This is also the month of the Messier Marathon named after
Charles Messier, a French comet hunter in the 18th century. As he
looked at fuzzy comets, he noticed that some of the objects aren’t moving
– and correctly concluded that they’re not comets (which orbit our
Sun and thus move). So he started a list of all those fuzzy, not-moving
objects, from M1 to M110, with the single objective of telling fellow comet
hunters: “hey buddy ( ‘ allocopain ’), don’t look at
these – boring.” Well, as it turns out, these are great deep sky
objects. The term “deep sky” makes sense because the closest ones
are a few hundred lightyears away, e.g. the open cluster M45 Pleiades,
the star nursery M42 Orion Nebula, and the planetary nebula M57 Ring Nebula;
some of the ones at a few thousands of lightyears away are the Supernova
remnant M1 Crab Nebula, the globular (dense) star cluster M13 Hercules cluster;
and some of them are millions of lightyears away, M31 Andromeda
Galaxy, M104 Sombrero Galaxy. All in all, the list contains lots of exciting
objects to look at that are in fact visible with a good telescope under a dark
sky. And they have a shape which makes them extra pretty (that’s how the
Sombrero Galaxy got its name). For astronomers, March means Madness, as
we’re able to see all those in a single night. A great web site with
photos is http://www.seds.org/messier/
.
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It's cold outside. But the nights are long and the hardy astronomer is
warmly dressed and enjoys an Eastern sky filled with 9 of the 25 brightest
stars. I love this winter sky.
The view is due East in the early evening or South later during the night. The
dominating constellation is Orion, the Hunter. It's many people's
favorite because of its brilliance. Four stars (including red Betelgeuse and
blue Rigel) arranged in a rectangle outline the body, while three stars
make the belt with the Orion nebula (great for naked eye and binoculars!) as
the sword beneath it. Above Orion you find Taurus , part of it shaped
like an arrowhead with red Aldebaran, and above that are the Pleiades,
the Seven Sisters, also a must for binoculars. To its left is the pentagon
Auriga with yellow Capella . Beneath Auriga is Gemini
with Castor and Pollux, the twins. And then we close this circle towards
the horizon, with Procyon and the Number 1: Sirius, the brightest star
in the entire sky.
Of course, all these bright stars and beautiful constellations build only the
background for Saturn and ultra-bright Jupiter, at least during the upcoming
winters. Try to see Jupiter's moons and Saturn's rings with a small
telescope or strong binoculars (use a tripod or hold steady by putting your
elbows on your car roof).
Reddish Mars is still visible low in the Southwest early in the evening.
Also visible this month is Mercury: "it is an elusive but exciting target
for the first three weeks of January. It's at its greatest elongation (apparent
separation from the Sun) on the 11th. For about 10 days before and after, you
can spot Mercury as a solitary light very low in the west-southwest
about 45 minutes after sunset." (www.skypub.com)
Tidbit: Earth was closest to our Sun on January 2 at 91.4 million miles,
compared to its farthest of 94.5 million miles on July 6.
The Eastern sky each January, South during February, and West in March.
The Sky in November 2001
This is this year’s last month of trying to find Uranus (with binoculars) - but you need to be in a very dark backyard. Start shortly after dusk. First find the teapot-shaped Sagittarius on the Southern horizon (you hold the handle in your left hand and you gently pour). To the upper left you see two fairly bright stars: Alpha and Beta Capricorni in the diagram. Now use the supplied chart: look at them with your binoculars, the upper one is actually a multiple. Now go left and you'll see four stars in an almost horizontal row. Put the one on the left in your binoculars: above it are three fainter stars in a vertical row - and to the right of them is Uranus! How do we know? Because I told you! But seriously, Uranus moves across the stars - that's how we know. Make a drawing, then look at it a week later and Uranus will have moved further to the left. Also, reddish Mars, still in the South, will pass Uranus on November 25 and 26.
In the West the big summer triangle with Deneb, Altair and very bright Vega is finally setting. However, it’s time for the great winter spectacle of stars: the view is due East in the late evening after 9 pm (earlier in December). The dominating constellation would be Orion, the Hunter, if it wasn't for the planets. Orion is many people's favorite because of its brilliance. Four stars are arranged in a rectangle - red BETELGEUSE, blue RIGEL, Bellatrix , and Saiph - which outline the body, while 3 stars make the belt with the Orion nebula as the sword beneath it. Above Orion you find Taurus with an arrowhead including red ALDEBARAN and the guest Saturn, and above those are the Pleiades (also called Seven Sisters), a must for binoculars. To its left is the pentagon Auriga with yellow CAPELLA. Beneath Capella appear the twins CASTOR and POLLUX, together with really bright Jupiter. And then we close this circle toward the horizon, with PROCYON and the Number 1: SIRIUS, the brightest star in the entire sky.
With a good telescope, you can see Saturn's rings and even with normal binoculars you can detect Jupiter's four largest moons; but make sure to hold your binoculars very still, e.g. by supporting your elbows on a car roof.
As fall is advancing, I'm looking forward to the stars of winter. A beautiful patch of the sky flanked by Orion and Taurus encompasses many of the brightest stars and easily recognizable constellations. However, in October they're still rising after midnight , so I'll be talking about these next month .
As for the planets, Mars is still hanging on, low in the Southwest. But my favorite, Saturn, is emerging in the East. In early October you can easily see Saturn around 11 pm PDT , late in the month around 8 pm PST . When looking towards the Eastern horizon, you'll see three bright "stars" in a horizontal row. The left is Alnath , a star at a corner of the pentagon-shaped constellatoin Auriga. The one on the right is reddish Aldebaran , part of the bull's snout in Taurus - while Alnath is one of the horns; the other horn's star is on the horizon. The snout also looks like an arrowhead and is made of stars from the Hyades star cluster - a great object for binoculars. And in the middle is Saturn. You can see the rings in a modest telescope. (But please don't go out and buy a telescope just for that purpose. Please contact me or Doug Rice [Spanish and Astronomy Instructor] at the college if you want to acquire a telescope for christmas .) The most spectacular star cluster is also in Taurus and just above Aldebaran : the Pleiades or Seven Sisters. You may see between five and seven stars with the naked eye, but more than twenty with binoculars.
Jupiter rises about an hour after Saturn and will be a show piece all winter long - you can't miss it because it's so bright. With some binoculars, which you hold very steady, you will see some of its four moons. In a small telescope, you see those moons and perhaps the cloud bands on Jupiter.
It's fun to "bag" one planet after another, so I will outline during
the upcoming year how to get the others. Everybody has seen the bright
planets, and now you can consciously say that reddish one in the South is Mars,
that one rising in the East is Saturn, and that really bright one late at night
in the East is Jupiter. Soon Venus will become an evening planet
again. Mercury, Uranus and Neptune (I'll explain that next summer) are a
little harder to catch, but still very possible to find with binoculars.
For a more thorough account, check the October issues of "Sky & Telescope" or "Astronomy" magazines (some libraries carry one or the other).
The Sky in July 2001
The main (and only easily visible) evening planet during July is Mars. It starts out in the Southeast, then progresses to the South, first moving West and getting closer to Scorpio’s red star Antares, which you find just to the right of Mars, then receding and moving slightly east from it.
But a spectacle of planets awaits early risers during dawn starting on July 10, with the best day being July 13. However, “early” means 4 a.m. That’s when you see bright Venus 15 degrees above the Eastern horizon, just to its left is a rather faint Saturn, and even further to the left and just above the horizon is bright Jupiter with a faint Mercury right next to it.
An exciting event happens in the morning on July 17 when our Moon occults Venus: which simply means that our Moon moves in front of Venus.
Finding our Moon in broad daylight isn't very hard at all when you know where to look. This is 3 days before the new moon and our Moon moves roughly 13 degrees each day. Multiply 13 degrees by 3: the crescent moon is about 40 degrees west of our Sun. Since our Sun is pretty high in the Southeast, you'll find this crescent Moon pretty high in the Southwest. [That alone is an accomplishment (to find our Moon in broad daylight) and can be repeated every day as long as you know how many days you're away from new or full moon.]
In order to see Venus during daylight, you probably need binoculars or a telescope. There is one major caution: never under any circumstances turn to our Sun and look at it with binos or a telescope! You could have permanent eye damage as the focused heat first fries the telescope's lens and then your retina!
Of course, it's save to put a telescope on our Moon, Venus, or even the blue sky (just make sure you're a safe distance away from our Sun). From about9:00 am PDT on, Venus will be very close to the crescent's upper left. It will be tough though since contrast between Venus and the blue sky is low. At exactly 9:24 am , the crescent will occult Venus. The planet will reappear at 10:43 am behind the dark side of our Moon (which will be even more difficult since you can't use the crescent as a guide anymore).
As I’m pointing my own telescope at Venus and Moon, I'll be using
a yellow filter since that will enhance Venus as it reduces the sky's blue
light. Still, it will be a challenge even for me since I haven't done
this for a while.
The Sky in December 2000
The highlights for this month are three very bright planets, a partial solar
eclipse and the bright stars of winter.
Ultrabright VENUS can be enjoyed for about two hours after sunset above the SW
horizon.
The bright stars of winter are found due East in the evening or South later
during the night. The dominating constellation is Orion, the
Hunter. It ?s many people?s favorite because of its
brilliance. Four stars arranged in a rectangle (with red BETELGEUSE, blue
RIGEL, Bellatrix , and Saiph) outline the body, while 3 stars make
the belt with the Orion nebula as the sword beneath it. Above Orion you
find Taurus with an arrowhead including red ALDEBARAN, and above that are the
Pleiades, the Seven Sisters, a must for binoculars. To its left is the
pentagon Auriga with yellow CAPELLA. Beneath Capella appear
CASTOR and POLLUX, the twins. And then we close this circle towards the
horizon, with PROCYON and the Number 1: SIRIUS, the brightest star in the
entire sky.
Of course, the above directions become confusing this month because bright
JUPITER and SATURN are smack in the middle of Taurus and you?ll find them
first and then look for the other stars. Jupiter and Saturn make a nice
triangle with the Pleiades above Saturn and Aldebaran beneath
Jupiter. Holding binoculars very steady, you should be able to see moons
to either side of Jupiter and ?ears? to either side of Saturn (
binos can?t be focused good enough to reveal the ring structure).
If you get up really early, you will see a fourth planet. But reddish
Mars will be visible for most of next year anyway, so there is no hurry here.
The big event in the morning on Christmas day, December 25, is a partial solar
eclipse for all of North America . This means that our Moon will
obscure up to 40% of our Sun, from 8:30 am to 11:00 am . You
may view our Sun safely with special solar eclipse glasses (the January 2001
issue of Astronomy magazine contains a couple; in stores right now), or,
according to the August 1999 issue of Sky & Telescope , ?Welder's
filters of shades 12 and higher? may be used. I personally would
prefer Welder ?s filter of shade 14. Other so-called filters may
not be safe (of course, regular sun glasses are out of the question) and may
lead to temporary or permanent eye damage. And, under no circumstances,
use binoculars or a telescope to view our Sun, not even with the safe solar
filters: the larger lens or mirror will intensify our Sun ? s light and
burn a hole right through the solar filter and then through your retina!
You have to make do with the small image that the eclipse glasses or
Welder ?s filter will give you. And, in any case, just to be on the safe
side, use caution and since you 're inexperienced , do not look at our
Sun for too long with the safe solar filters.
The Scottsbluff Library has ordered 100 eclipse glasses that can be purchased
for about $1 a piece (covering only their expenses). The last time they
are open before Christmas day is on Saturday, 12-23, 9 am to 6 pm.
Unfortunately for myself, I?ll be in Europe and miss this partial
eclipse. And, since I return in late December, I will also miss the total
lunar eclipse on January 9 in
Another option are some candy
and Baseball card wrappers. (Leave out because kids don't know which
candy to buy.)
They look like Aluminum foil but are Mylar and
block most of our Sun's intense visible radiation. I use two of those
sandwiched, which also enhances the contrast. But again, use these
cautiously and for short times (a few seconds) and never, never, never with
binoculars or a telescope!!
The Sky in July 2000
Two of my favored constellations are prominent just above
the southern horizon during July and August: Scorpius in the shape of a
scorpion with a bright, red Antares as its heart; Sagittarius in the
shape of a teapot, held in your left hand. The Milky Way runs right
through them. Using binoculars, you'll find many interesting
objects. Drive just out of town, stop at a safe place and, to stabilize
the binoculars, put your elbows on the car roof. Follow the Milky Way
from Sagittarius through the Northern Cross overhead down to the W in the
North. Go back to the South and find the star clusters M4 next to
Antares , M6 and M7 next to the scorpion's tail and the Lagoon cloud M8 above
the teapot's spout.
As far as planets are concerned, pretty much everybody has
seen Jupiter, Saturn, Mars and Venus. Here's a chance to find two other
planets inCapricornus (after 10 pm in early July, later at any time in the
evening). Start with
Another binocular sight during July and August is comet
Linear. It appears above the Northern horizon. Due to space
restrictions, the chart isn't printed here. So please go to my web site
at http://www.wncc.net/ astronomy , click on "Lectures", then
"The monthly Sky". There's a link to a finder chart for comet
Linear (outdated now; May 2002 ) .
Also, check the current issues of Sky & Telescope and Astronomy magazines
in local libraries. (The same goes for information on the July eclipses.)
Last but perhaps least, July 2000 contains three
eclipses. The partial solar eclipse on July 1 was visible from
PS The Scottsbluff Public Library organizes a public
evening at the Westmoor on July 11 (on the 12th if inclement weather) at
8:30 pm . Kids, their parents and the general public are
welcome. Jamelee Clark will present.
The sky in January 2000
Total lunar eclipse
This is a naked eye and/or binocular event.
The total lunar is observable from everywhere in the Americas on Thursday evening, January 20. Obviously, this is when we have full Moon. And lunar and solar eclipses (about 2 or 3 every six months) are the only times when there are any shadows involved!!!! I emphasize this because shadows have absolutely nothing to do with, never will, and are completely, irrevocably unrelated to our Moon's phases.*
The eclipse starts at 7 pm MST when the Western limb of our
Moon touches the most Western edge of Earth's shadow. The decrease in
brightness is so little that only by 7:45 should we be able to notice
something. The total eclipse begins around 9 pm and lasts until
10:20 . Our Moon is expected to shine then at only a 1/10,000 of its
normal brightness, about the same as Jupiter which you find in the
Southwest. Also, look out for Gemini's Castor and Pollux to the
northwest of the eclipsed Moon, while the pretty Beehive cluster is just to the
east. Binoculars are the ideal instrument to watch the lunar eclipse and
to peek at the Beehive. The eclipse consummates at 12:30 am
but for all practical purposes should be over by midnight .
I have astronomy class from 6 to 9 pm, so we'll be in and out to
observe next to the Eastern parking lot. Some kids from
Appendix:
Check Fred Espenak's eclipse page at http://sunearth.gsfc.nasa.gov/eclipse/OH/ OH2000.html .
See an explanation for our Moon's phases and you may want to read through this and other trivia. ("Our Moon orbits the Earth and reflects our Sun's light, too. Its phases depend on the angle we view it in relation to our Sun. Our Moon's phases have nothing to do with its own, Earth's, or anybody else's shadow. But eclipses do.")
Whenever you see me with telescopes out there
next to the lab, stop by. I'm positive that you will not disturb my class
(this note is meant especially for Staci ).
The sky in December 1999
Christmas is upon us and your best astronomy buy is … a
starfinder which runs between $3 and $10 at the Deere Crossing,
Copperfield , department stores, and the WNCC bookstore.
Venus is the bright object in the East pre-dawn sky. Our Moon will be
full on December 21/22 and extra large because it’s at
its orbit’s perigee (closest point to Earth). Mars is still
low in the Southeast after sunset, moving through Capricornus (closest to
Uranus on December 13, try binoculars). Jupiter is now the bright object
high in the South, Saturn to its lower left. In the Southeast
you’ll find the constellation Orion, the star cluster Pleiades (Seven
Sisters, left from Saturn), and many bright stars: Sirius, Procyon, Aldebaran,
Castor, Pollux, Capella … check your newly acquired
starfinder. On the back it usually lists the planet positions for the
next 4 years. Also check the current Astronomy and Sky & Telescope magazines
in the libraries.
Some people may also be lured by department store telescopes which advertise as
420x magnification and come with flashy pictures of Saturn and comets (they
waste about $100). I call them attic-dust- collectors, other astronomers
call them trash scopes. Well, you can actually use them for looking at
our Moon or see Jupiter’s moons (appearing as dots). But
binoculars would be just good enough for that. I know , this is a really
tempting gift to present to a youngster. But, please, please, please,
don’t do it! I say this for selfish reasons, (a) I want
people to enjoy astronomy, (b) I don’t want anybody to get
frustrated by a wobbly telescope that produces blurry images, and (c) if you
keep enjoying astronomy you might even take my class.
Two things you have to look for when you want to buy a telescope: a stable
mount for the telescope and that the finder scope is aligned with the
telescope. Both are next to impossible to attain with these
attic-dust-collectors. My advice: buy a starfinder, stay with the
binoculars that you perhaps already own, call me at 635-6056 for advice, stop
by my WNCC office C-2 to pick up an Orion catalog of which I have plenty (or
order one through www.telescope.com), and/or get something else (flashy) for
the youngster.
Of course, you could put the dust-collector in the living room and show it to
your friends, "Look at this wonderful, wobbly telescope. It has 420x
power but it doesn’t show a darn thing. But here, see that
very blurry thing? I’m not sure what it’s pointing at
but it might be Saturn."
The Sky in November 1999
It's a good month for planets. Venus: before and
during dawn look for the very bright beacon in the East. Mars: look
during dusk for a red object low in the Southeast. Uranus: see the finder
chart. You also need binoculars (any will work). Do this after
dusk. It works best without moonlight and little light pollution.
Find A & B Capricorn first at about 30 degrees (at 6:30 pm, at a later time
it will be lower) above the Southern horizon, then use your binoculars to find
the triangle beneath them, then go left to find another fairly bright star;
Uranus and some other stars are to its right. Make an accurate drawing of
the about four or five bright objects in your bino's field of view.
Return one or two weeks later and make another drawing. Uranus is the one
that will have moved. Jupiter: it's a bright object after sunset in the
East. Saturn: it's to Jupiter's lower left, but it's fainter.
You would need a telescope to see Jupiter's four moons and Saturn's rings.
On November 15, between 2 and 3 pm , Mercury will transit
the sun. I advise everybody not to look at the sun, especially not with
any kinds of optics. It's dangerous and you could lose your
eyesight! Instead, I'll have equipment put up next to the East parking
lot at WNCC. I'm using special solar filters to make looking at the sun
safe. Mercury is very small compared to the sun, so it's hard to spot and
distinguish it from sunspots. It also just grazes the sun's edge, so I
wonder how good it will actually show up.
This month promises to present a great Leonid meteor
storm! (I don't promise that, so donut blame me if it doesn't turn
out to be great.) Look out during the nights of November 16/17, but
especially 17/18 and finally 18/19, very late at night (about 1 to 2 a.m. -
sorry). Look anywhere in the sky as the meteors seem to come from the
East (where the constellation Leo is rising). You should be outside of
town. Wear warm clothes! Take along a reclining chair and lie back
and watch the stars. No binoculars needed. And no, except for Geoff
Smith, please don't show up at my house.
For more information on the planets this month, the Mercury transit and the
Leonid meteors, check the November issues of "Astronomy" and
"Sky & Telescope" at the public libraries.
Andreas Veh,
WNCC Instructor, for questions call 635-6056 or e-mail vehk@wncc.net
The Sky in March 1999
Look out for these planets during the next days. Saturn will be gone by
the beginning of April. But Mars and Venus will visible until the end of
summer.
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The very close conjunction on February 23 was Jupiter and Venus. The
accompanying diagram illustrates why they appeared so close from our vantage
point (Earth). The next time this happens in the evening sky
(twilight) will be in June 2002, but it won't be that close. After that
in 2015 (again twilight). Who were those people who called the Air Force
with their alleged UFO sightings? Again, during this coming week use
Venus and Jupiter as pointers to find Mercury (fainter) just above the western
horizon during dusk.
Once again we have a blue moon at the end of the month. A neat article
about the phrase "once in a blue moon" appears in the March 99 issue
of Sky & Telescope (at the public library). To associate this phrase
with the second full Moon in a calendar month is very recent folklore (in the
As for the stars, take advantage of our mild weather, go outside and enjoy the bright stars of winter, Orion, Sirius, Procyon, Capella, etc., all of which appear in the Southern part of the sky. You can't miss them because all of them are bright. If you want to know which is which, buy a starfinder at the WNCC bookstore, Copperfield , or the Deere Crossing.
The Sky in December 1998
The planets this month are still Saturn and
Jupiter. The brightest object in the sky is Jupiter, high in the
South. Saturn is about 3 fists (at arm's length) to the East of Jupiter,
somewhat fainter and appearing yellow-red.
Towards the end of the month look out for bright Venus above the Western
horizon during dusk.
During December, after 8 pm, count the really bright stars
above the Eastern horizon: depending on what you consider really bright,
there are about a dozen of them. Orion contains red Betelgeuse and
blue Rigel . Around Orion you find Taurus with an arrowhead
including red Aldebaran , and above that are the Pleiades (also called
Seven Sisters), a must for binoculars. Then there are yellow
Capella, beneath it appear Castor and Pollux , the twins, and finally
closing the circle toward the horizon, Procyon and Sirius, the brightest
star in the entire sky.
I advise you to get a "Star Finder", which
is a card board dial showing constellations and bright stars. You adjust
time and date and thereby can use it year-round. It certainly is worth
the $10 price tag (or less). I've seen Star Finders at the Deere
Crossing, and my students buy theirs at the WNCC bookstore. Also,
try Copperfield and Horizon.
PS If you need an astronomy expert, ask a student or
teacher from Lincoln Elementary in Gering. Or try my website at
"www.wncc.net/astronomy" or this one:
"dir.yahoo.com/science/astronomy".
The Sky in November 1998
This month promises to present a great meteor shower!
(I don’t promise that, so don’t blame me if
it doesn’t turn out to be great.) Every 33 years or so the
Leonid meteors pelt the Earth. Look out during the nights of November
16/17 and 17/18, especially in the morning (about 1 to 2 a.m. local time -
sorry). Look anywhere in the sky as the meteors seem to come from the
East (where the constellation Leo is rising). You should be outside of
town. And wear warm clothes!
I understand that the 1966 Leonids were fantastic (an estimated
100,000 meteors per hour) and that in 1833 it was such a spectacle that people
thought the world would come to an end while others woke up in the middle of
the night thinking their town was on fire. It truly could be a spiritual,
awesome view, even nowadays. But the possible magnificence of meteor
showers is not predictable, so we have to be content with what we get.
For more information check the November issues of "Astronomy" and
"Sky & Telescope" at the public libraries.
Two planets rule in November: you can't miss Jupiter, it's the
bright beacon high in the Southeast. Hold your binoculars very stable and
you might see some of its 4 bright moons. They're close and lined up with
Jupiter. Saturn follows suit, it’s about half way
between Jupiter and the Pleiades, a small but beautiful star cluster rising
early in the East. You would need a small telescope to see Saturn’s
rings.
This is this year’s last month of trying to find Uranus (with
binoculars) - but you need to be outside of town. Start just after
sunset. First find the teapot-shaped Sagittarius on the Southern horizon
(you hold the handle in your left hand and you gently pour). To the upper
left you see two fairly bright stars: a and B Capricorni in the
diagram. Now use the supplied chart: look at them with your binoculars,
the upper one is actually a multiple. Move a little down until you get
the small triangle. Put this triangle on the right of your
binocular's field. In the middle is a single star and on the left (same
distance) 3 stars: the lower one is Uranus. How do we know? Because
I told you! But seriously, Uranus moves across the stars - that's how we
know. Make a drawing, then look at it a week later and Uranus will
have moved further to the left.
In the West the big summer triangle with Vega (very bright), Deneb
and Altair is finally setting. However, it’s time for
the great winter spectacle of stars: the view is due East in the
late evening (after 8 pm ). The dominating constellation is Orion, the
Hunter. It's many people's favorite because of its brilliance. Four stars
arranged in a rectangle (with red BETELGEUSE, blue RIGEL, BELLATRIX, and
Saiph ) outline the body, while 3 stars make the belt with the Orion nebula as
the sword beneath it. Above Orion you find Taurus with an arrowhead including
red ALDEBARAN, and above that are the Pleiades (also called Seven Sisters), a
must for binoculars. To its left is the pentagon Auriga with yellow
CAPELLA. Beneath Capella appear CASTOR and POLLUX, the twins. And
then we close this circle toward the horizon, with PROCYON and the Number 1:
SIRIUS, the brightest star in the entire sky.
Two planets rule: you can't miss Jupiter , it's the bright
beacon in the Southeast. Hold your binoculars very stable and you might
see some of its 4 bright moons. They're close and lined up with
Jupiter. Saturn rises after sunset, just a little North of East.
You would need a small telescope to see the rings.
To find Uranus (with binoculars) use the supplied chart: first find the
teapot-shaped Sagittarius above the Southern horizon (you hold the handle in
your left hand and you gently pour). To the upper left you see two fairly
bright stars: a and b Capricorni in the diagram. Look at them
with your binoculars, the upper one is actually a multiple. Move a little
down until you get the small triangle. Put this triangle on the right of
your binocular's field. In the middle is then a single star and on
the left (same distance) 3 stars in a row: the lower right one is Uranus.
How do we know? Because I told you! But serious, Uranus moves
across the stars - that's how we know. Look at it in November and it will
have moved to the left.
A very easy configuration of stars is the big summer triangle with Vega (very
bright), Deneb and Altair - even easy to see in town. Deneb
is the brightest star in Cygnus, the Swan, which looks like a cross. The
summer triangle is now directly above our heads. From a very dark site in
The Sky in June 1998
I recently watched Carl Sagan’s Contact: Good movie,
correct science. The only personal opinion I’d like to allow
myself in this astronomy column is that in my understanding science and
religion complement each other, science trying to answer the "how it
works", religion and philosophy attempting to answer the "why".
Unlike with other movies, I expected Carl Sagan to get all the
science right - and of course he did. He also avoided two things: there
is no mumble-jumble on how the transport machine would work (nobody would know
or could imagine) and there are no fancy aliens (nobody would know what
they’d look like).
Anyway, Jodie Foster’s character received radio signals from
Vega (this is fiction) and stopped by there before traveling through several
wormholes (also fiction). And Vega is the fifth brightest star (as seen
from our part of the Galaxy), 26.5 lightyears away ( that’s a
distance equal to 150 trillion miles), a white A0
The Sky in April 1998
This is the month of the fixed stars as there are no planets in the evening
skies. Of course, early birds can observe Venus and, later in the month,
Jupiter above the Eastern horizon.
But for the night owls among us, we'll see the winter constellations and their
brilliant stars disappear in the West. Gemini (two bright twin stars),
Taurus (snout and horns of a bull), the Pleiades (a mini-dipper), Orion (the
hunter), and the brightest star Sirius will be gone very soon. High in
the South Leo, the Lion , dominates. In the East ,Bootes , the
Bear Guard (looks like a kite or ice cream cone), and the bowl shaped Northern
Crown appear. In the North the constellations Cassiopeia (the W) and the
Big and Little Dipper (Big and Little Bear) are as beautiful as always.
Our Moon brightens the evening sky during the beginning of the month.
Since it rises one hour later every day, the best time for your star party
would be after the full Moon on April 12. Go outside of town. Since
How do you find the North star ? Take the last two stars of the Big
Dipper's pan and mark off a distance five times their separation, towards
North. You'll always end up at Polaris, which is the last star of the
smaller and fainter Little Dipper.
How do you find Arcturus, the reddish star in Bootes? Follow
the curved pattern of the Big Dipper's handle and you'll end up at
Arcturus , the brightest star in the Eastern sky.
Hint: Get a star finder, possibly at a bookstore.
The Sky in February 1998
The planets are gone from the evening sky. Except
for Saturn, which is still shining brightly in the South/Southeast.
Pretty lonely. But last month's great assembly of winter constellations
(Orion, Taurus, Gemini ) and their super-bright stars are still
there. This month they progress further from the East to the South - or
so it seems when watching them from week to week.
Another object is going the other way: Our Moon. New Moon (it and
our Sun lied in the general same direction) was January 27. When you
observe our Moon from one day to the next, you'll notice that it keeps moving
further East away from our Sun. It also becomes fuller as we can watch it
from a more favorable angle. Which means that the phases of our Moon have
absolutely nothing to do with anybody's shadow. Nothing, nothing,
nothing! It's the angle between Earth, Sun and Moon that makes the phases:
Half of our Moon reflects the Sun's light at any given time. At full
Moon, when it's opposite the Sun, we see the entire lit-up half. When
it's close to the Sun, we can see only a tiny portion of that lit-up half: a
sliver, in the West evening sky in early and late February and in the East
early morning sky between the 22 and 25.
Then on the 26 of February a solar eclipse can be watched from the
Caribbean. That's the event when really some body's shadow is
involved. Live internet pictures can be viewed via www.skypub.com/eclipses/s980226c.html
(outdated link) . A solar eclipse
happens only every 6 months and is visible only from those regions on Earth that
are touched by our Moon's shadow.
PS This month shall mark the founding of an Astronomy Club in
Andreas Veh
The Sky in January 1998
It's cold outside, especially in the valley. But the nights are long and the
hardy astronomer is warmly dressed and enjoys an Eastern sky filled with 9 of
the 25 brightest stars. I love this winter sky.
The view is due East in the early evening or South later during the night. The
dominating constellation is Orion, the Hunter. It's many people's
favorite because of its brilliance. Four stars arranged in a rectangle (with
red BETELGEUSE, blue RIGEL, BELLATRIX, and Saiph ) outline the body,
while 3 stars make the belt with the Orion nebula as the sword beneath it.
Above Orion you find Taurus with an arrowhead including red ALDEBARAN,
and above that are the Pleiades, the Seven Sisters, a must for
binoculars. To its left is the pentagon Auriga with yellow
CAPELLA. Beneath Capella appear CASTOR and POLLUX, the twins. And then
we close this circle towards the horizon, with PROCYON and the Number 1:
SIRIUS, the brightest star in the entire sky.
Of course you may also look out for the Big Dipper low on the Northern
horizon, the North star above it - which is only 49th in brightness -, the
Summer triangle in the West (another 3 of the brightest stars), and I hope
you're still watching the planets because Venus and Jupiter are splendid and
Mars and Saturn fairly bright as well (all South or low Southwest) - some of
these during the very early evening only.
Andreas Veh
Astronomy Instructor, WNCC
PS It's still time till Friday, the 16th, to sign up for one of my two
Astronomy classes, at 635-6000. My classes meet MWF 9-10 a.m. with lab to be
arranged, or Thursday, 6-9 p.m.
The Eastern sky each January, South during February, and West in March.
The Sky in December 1997
It's been the fall of the planets. The spectacle begins right after sunset,
around 4:30 p.m. Take your family outside and face South.
You can't miss the ultra-bright Venus just above the SW horizon and Jupiter
fairly high (30 degrees) above the Southern horizon.
Start with Venus, since it will set before 6:30 p.m.: Reddish Mars is about a
hand width on the right of Venus. Watch them disappear in the lower atmosphere.
Jupiter and Saturn will be there for the rest of evening. The ringed planet is
rather inconspicuous, a fairly bright object about 40-50 degrees above
the SE horizon.
There will be a public telescope viewing on the WNCC East parking lot
on Thursday, December 11th, between 5 and 6 p.m.
The above diagrams show what you can expect with a 50 to 100
magnification. Saturn on the left, then Jupiter with 3 of its 4 bright
moons, then the sliver of Venus, and finally tiny Mars.
Mars and Venus are close in size, but since Mars is very far from Earth right
now, and Venus at 40 mill. miles is really close, they appear so
differently in size and brightness. With Jupiter being 10 times larger
than Venus and at 400 mill. miles 10 times farther away, it appears almost as
bright as Venus
There has been some hype recently about seeing all planets
"aligned". Honestly, my students and I have been excited all fall
because we've been enjoying Venus, Jupiter, and Saturn the entire time. The
other planets are fainter and you need to know exactly where to look.
Here's a finder chart, but please note that all planets appear as dots only in
the sky:
This is a more colorful image, but the above negative image is nicer for printing.
To my WNCC Astronomy home page
.