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The Night Sky of January

Dr. Wayne Wooten
Professor of Astronomy

For January 2015, the Moon will be full on January 4. It will interfere greatly with the peak for Quadrantid Meteor Shower on the same morning, with perhaps 30 meteors per hour coming out of the NE in the morning sky. The first two weeks find the moon waning in the morning sky. The waning gibbous moon sits 4 degrees south of Jupiter on January 7th.

The last quarter moon on January13th is just north of Spica. The waning crescent moon passes 2 degrees north of Saturn in the dawn on January 16th. The new moon is on January 20th, and begins the Chinese New Year. It has a nice conjunction with Venus and Mercury on January 211st, about 45 minutes after sunset; the moon will be just to the right of Venus, and just above Mercury, a good photo op! The waxing crescent moon passes just north of faint Mars on the following evening. The moon is first quarter on January 26th.

Mercury and Venus play tag in the SW twilight early in January. Venus is by far the brightest, a tiny bright gibbous disk in the telescope as it returns from behind the sun into the evening sky. Look of fainter Mercury just below and to the right of Venus, and Mercury comes closest to Venus on January 10th, with Mercury only .5 degrees (a moonís diameter) to the lower right on that evening. But now Mercury passes between us and the Sun, and falls lower; as noted, the crescent moon joins the show on January 21st. Mercury is gone into the sunís glare by monthís end, but Venus is dominate the dusk for most of 2015. Mars is distant and faint, in the evening sky moving eastward in Capricorn; Venus will overtake it in early February.

Jupiter dominates the eastern sky in late evening. It is at opposition, rising at sunset, early next month. It lies west of the head of Le and rises at 9 PM on New Yearís Day. By monthís end, you can see Venus about to set at the same time Jupiter is rising. In the telescope, Jupiterís four moons are visible, and their changing patterns in a matter of minutes are fascinating. Saturn rises about 3 AM as January begins, and will reach opposition in May this year. It currently lies just above the claws of Scorpius.

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 Pegasusíí 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 Andromedaís 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 Perseusí 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.

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. You 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. It is part of a huge spiral arm gas cloud, with active starbirth all over the place. You should be able to glimpse this stellar birthplace as a faint blur with just your naked eyes, and the larger your binoculars or telescope, the better the view becomes. This monthís highlight photo is of the Orion Nebula

Last but certainly not least, in the east rise the hunterís 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 Yearís sky feast.

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