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The Night Sky of January

Dr. Wayne Wooten
Professor of Astronomy

The waxing gibbous moon passes below Mars on January 3rd. At month’s end, it will not miss, but occult Mars for 41 minutes! The full moon is January 6th. The last quarter moon is January 14th. The new moon is January 21st. The waxing crescent lies just to the upper left of the fine pairing of brilliant Venus just above much fainter Saturn in the twilight on January 23rd. The waxing crescent moon lies just below Jupiter on the evening of January 25. It is first quarter on January 28th.

The fun begins in the SW sky at 11:32 p.m. on January 30, when the dark side of the waxing gibbous moon suddenly blots out bright red Mars as it passes in front of it for the next 43 minutes, as seen from Pensacola. These events will vary in other locales. The occultation will end when Mars reemerges along the moon’s north west limb near the craters Atlas and Hercules at 12:13 a.m.. This will be a spectacular photo opportunity for folks with large telescopes. In a preview, here is the close call back on December 7th, when the Full Moon just missed Mars in our area. Note how tiny Mars appears compared to the Moon; in reality, it is twice as large as our satellite.

Remember that starting at 11:32 p.m. on January 30th, the moon’s dark eastern limb will cover the planet for 43 minutes! It will take about a minute for the planet to completely disappear behind the moon, so this will make a very dramatic video with your smart phones through large telescopes. Catch it!

Mercury appears briefly at midmonth in the dawn sky. Venus returns back to the evening sky for most of 2023; she is low in SW an hour after sunset on January 1st. Moving away from the Sun, she overtakes slow moving Saturn, passing only .3 degrees south of the ringed world on January 22nd. If it is clear enough, you may see the very thin crescent moon on the horizon beneath them then; look about 40 minutes after sunset. By month’s end, Saturn is lost in Sun’s glare, but Venus still higher and brighter in west.

As noted, Mars is in Taurus, well up in eastern sky at sunset, and the Moon’s target for the occultation of January 30-31! Now is the best time to observe it, since it just passed opposition last month, and is well up in the sky for northern hemisphere observers now.

Jupiter is also getting lower in the west, to follow Saturday behind the Sun by March. But still worth watching for the Great Red Spot, which is unusually prominent and quite red of late, and its four Galilean moons. As noted, Venus laps Saturn on the 22nd, and the Sun swallows it up by month’s end.

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 December 30th visit the www.skymaps.com website and download the map for January; 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.

The constellation Cassiopeia makes a striking W in the NW. 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 precede 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. The blue color of the Pleaides is enhanced even more by the beautiful reflection nebula, where the dust accompanying this cluster, "so young it is still running around in its diapers."

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.

South of Gemini, Orion is the most familiar winter constellation, dominating the eastern sky at dusk. The reddish supergiant Betelgeuse 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 star birth 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.

While M-42 is a emission nebulae, shining reddish from the ionization of its hydrogen gas by hot young stars forming inside it, at Orion’s right foot is brilliant Rigel, one of the most luminous blue super giants ion the Galaxy, about 50,000X more luminous than our Sun.

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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