The Sky of January
Dr. Wayne Wooten
Professor of Astronomy
Escambia Amateur Astronomers' Association
For January 2009, the Moon will be a waxing crescent as the month begins. It passed about 3 degrees north of Venus on New Year's Eve. The first two weeks find the moon waxing in the evening sky. First quarter moon sits high in the sky and
half-lit at sunset on January 4th. The full moon for January is the Old Moon, or the Moon after Yule; it occurs on January 11th. The last weeks of January finds the moon waning in the morning sky, passing 6 degrees south of Saturn on January 15th ; both rise about 9 PM due east. The new moon is on January 26th, and
creates an annular solar eclipse visible in the Indian Ocean. The next eclipse season, in July, creates a very long total solar eclipse, well seen in China. Alas, no eclipses of either type for us in 2009.
While the naked eye, dark adapted by several minutes away from any bright lights, is a wonderful instrument to stare up into deep space, far beyond our own Milky Way, binoculars are better for spotting specific deep sky objects. For a detailed map of northern hemisphere skies, about January
1st visit the www.skymaps.com website and download the map for January 2009; it will have a more extensive calendar, and list of best objects for the naked eyes, binoculars, and scopes on the back of the map. Also available as the next month begins is wonderful video exploring the January 2009 sky, featuring many
different objects, available from the Hubble Space Telescope website at: http://hubblesite.org/explore_astronomy/tonights_sky/.
Venus dominates the evening sky; telescopically she appears as a small, gibbous disk. She is still on the far side of her orbit. It was Galileo in 1611 who noted that Venus goes through this entire phase cycle, and correctly deduced this proved she orbited the Sun, not us. Covered with
sulfuric acid clouds, her bright disk reveals no visible details in the scopes.
This is an interesting month for Saturn. Children will be disappointed, for the famed rings are vanishing! My photo of it in October 2008 shows the rings almost edge on, and they are even
thinner now; you may not even spot them with many amateur scopes! We just passed through winter solstice, with our southern hemisphere tilted most sunward, at 23.5 degrees. Saturn did this seven years ago, and the wide open bright icy rings, at a 27degree tilt, made the planet twice as bright as it is currently.
Now is the equinox, with Saturn's equator and the very thin rings that encircle it, pointing directly at the sun. A bonus is that when Saturn's big moon Titan passes in front of Saturn now, its shadow will transit the disk of the second largest planet. Amateurs are used
to these shadow transits with Jupiter's four big moons, but this is only at equinox for Saturn. On January 6th, you may catch the end of this as Saturn rises, but the next several such transits happen in daylight locally.
The square of Pegasus dominates the western sky. The constellation Cassiopeia makes a striking W in the NW. She contains many nice star clusters for binocular users in her outer arm of our Milky Way, extending to the NE now. Her daughter, Andromeda, starts with the NE corner star of Pegasus''
Square, and goes NE with two more bright stars in a row. It is from the middle star, beta Andromeda, that we proceed about a quarter the way to the top star in the W of Cassiopeia, and look for a faint blur with the naked eye. M-31, the Andromeda Galaxy, is the most distant object visible with the naked eye, lying
about 2.5 million light years distant. Overhead is Andromeda's hero, Perseus, rises. Between him and Cassiopeia is the fine Double Cluster, faintly visible with the naked eye and two fine binocular objects in the same field. Perseus contains the famed eclipsing binary star
Algol, where the Arabs imagined the eye of the gorgon Medusa would lie. It fades to a third its normal brightness for six out of every 70 hours, as a larger but cooler orange giant covers about 80% of the smaller but hotter and thus brighter companion as seen from Earth.
Look at Perseus' feet for the famed Pleiades cluster; they lie about 400 light years distant, and over 250 stars are members of this fine group. East of the seven sisters is the V of stars marking the face
of Taurus the Bull, with bright orange Aldebaran as his eye. The V of stars is the Hyades cluster, older than the blue Pleaides, but about half their distance. Mars now lies in the horns of Taurus as January begins, and was at greatest brilliance at opposition around last Christmas.
Yellow Capella, a giant star the same temperature and color as our much smaller Sun, dominates the overhead sky. It is part of the pentagon on stars making up Auriga, the Charioteer (think Ben Hur). Several nice binocular Messier open clusters are found in the winter milky way here. East of
Auriga, the twins, Castor and Pollux highlight the Gemini. UWF alumni can associate the pair with Jason and the Golden Fleece legend, for they were the first two Argonauts to sign up on his crew of adventurers.
South of Gemini, Orion is the most familiar winter constellation, dominating the eastern sky at dusk. The reddish supergiant Betelguese marks his eastern shoulder, while blue-white supergiant Rigel stands opposite on his west knee. Just south of the belt, hanging like a sword downward, is
M-42, the Great Nebula of Orion, an outstanding binocular and telescopic stellar nursery. Now that Saturn's rings are temporarily out of view, I would rate the complex nebulosities of the Great Nebula as the most beautiful sight
in the sky with scopes of ten inches or larger.
Last but certainly not least, in the east rise the hunter's two faithful companions, Canis major and minor. Procyon is the bright star in the little dog, and rises minutes before Sirius, the brightest star in the sky. Sirius dominates the SE sky by
7 PM, and as it rises, the turbulent winter air causes it to sparkle with shafts of spectral fire. Beautiful as the twinkling appears to the naked eye, for astronomers this means the image is blurry; only in space can we truly see 'clearly now'. At 8 light years distance, Sirius is the closest star we can easily
see with the naked eye from West Florida. You must be in south Florida to spot Alpha Centauri on June evenings. Below Sirius in binoculars is another fine open cluster, M-41, a fitting dessert for New Year's sky feast.
For more information on the Escambia Amateur Astronomers and our local star gazes for the public, visit our website at www.eaaa.net or call our sponsor, Dr. Wayne Wooten at PJC at (850) 484-1152, or e-mail him at firstname.lastname@example.org.
Read past issues of the Sky at Night