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The Sky of January

Dr. Wayne Wooten
Professor of Astronomy
Escambia Amateur Astronomers' Association

For January 2008, the Moon will be a waning crescent as the month begins. The waning crescent moon is passing about 6 degrees south of Venus on January 5th, then 4 degrees south of Jupiter on January 7th. The new moon occurs on January 8th. The next 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 15th. The Waxing gibbous moon will be just a degree north of bright red Mars on January 19th. The full moon for January is the Old Moon, or the Moon after Yule; it occurs on January 22nd. The last week of Januar6 finds the moon waning in the morning sky, passing 2.5 degrees south of Saturn on January 25th  both rise about 8 PM due east.

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 website and download the map for January 2008; 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 2008 sky, featuring many different objects, available from the Hubble Space Telescope website

Venus dominates the morning sky; telescopically she appears as a small, gibbous disk. She is now on the far side of her orbit, and will pass only .6 degrees north of Jupiter, the second brightest planet, on February 1st. 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 a fine month of observing red Mars, which came to the closest approach to earth until 2016 at the end of December.

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. On October 24, 2007, a faint, obscure comet, 17P/Holmes, suddenly exploded just east of Mirfak, the brightest star in Perseus, becoming a million times brighter than normal, and an easy naked eye object for about three weeks. The expanding coma grew larger than the size of the Full Moon in the sky, and in reality, since the comet is 1.5 times farther from us than the Sun is, the coma was bigger than the bright photosphere of our Sun! Alas, in early January it has faded from naked eye visibility.

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. The bright diamond of four stars that light it up are the trapezium cluster, one of the finest sights in a telescope. East of Betleguese is the fine stellar nursery, the Rosette Nebula, which is our highlight photo this month. This wonderful look at young stars climbing out of their stellar nest (photo at the top of this page) was made by EAAA member Bob Gaskin.

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.