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The Night Sky of January

Dr. Wayne Wooten
Professor of Astronomy

For January, 2019, the waning crescent moon is just above Venus in the dawn on New year’s morning, and midways between Venus and fainter Jupiter on the morning of January 2nd. The earth is closest to the sun (yes, that is right!) on January 3rd at 11 p.m., three million miles closer than it is at aphelion in July. It is our axial tilt, rather than the slight variation in our distance from the sun, that drives our seasons. Also on the 3rd, the waning crescent lies just north of Jupiter in the dawn, and just above faint Mercury on the predawn horizon on January 4th, and the peak of the Quadrantid meteor shower occurs just after midnight on the same morning; perhaps 40 meteors per hour will come out of the NE. The new moon is on January 5th. The waxing crescent passes south of Mars in the evening of January 12th.

The moon is first quarter on January 14th. The full moon on January 20th will give us a fine total lunar eclipse. The umbral eclipse beginning about 9:30 p.m.. Totality will start at 10:40 p.m., and the deepest eclipse will be at 11:10 p.m.. The total portion will end about 11:40 p.m., and the umbral eclipse ends about 12:50 a.m. on Monday morning.

After the “Wolf” Full moon, the waning moon is third quarter on January 26th. The crescent in the dawn is above Jupiter on the morning of January 30th, very close to Venus in January 31st, and midway between Venus and Saturn an hour before sunrise on February 1st. Ir will be just to the lower left of Saturn on February 2nd.

Mars is the only evening planet, and now far from earth, a fading red point moving north and east through the autumn zodiac in the SW evening sky in January. The morning sky has many more planetary groupings to see. Mercury is briefly visible low in the east as January starts, with the moon close to it on January 4th, but is gone behind the Sun for the rest of the month. Brilliant Venus moves eastward to overtake slower Jupiter by the middle of the month. The two are closest on January 24, with Venus passing 2.4 degrees above Jupiter. By the end of the month, Venus is well east of Jupiter, and Saturn comes from behind the Sun into the dawn sky as well.

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. 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 crew0.

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.

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. Below Sirius in binoculars is another fine open cluster, M-41, a fitting dessert for New Year’s sky feast.

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