December Skies Of The Gulf Coast

Dec 3, 2020

A full moon over Earth, seen by astronaut Ron Garan from the International Space Station.
Credit NASA

The last quarter moon occurs on Dec. 7, and the waning crescent moon passes one degree north of Venus in the dawn on Dec. 12. Get up earlier that morning and the next for the peak of the Geminid meteor show, coming from near Castor and Pollux overhead.

The new moon on Dec. 14 produces a total solar eclipse, but not for us. The center line cuts across Chile and Argentina, alas. The waxing crescent passes just three degrees below Jupiter and Saturn in the evening sky on Dec. 16; note the two planets are now less than a degree apart. They appear to merge for most of us with the naked eye on the evening of Dec. 21, with Jupiter passing only .1 degree south of Saturn, and their larger moons visible around them both in the same telescopic view about 6 p.m. in evening twilight.

Expect to see only the four large moons of Jupiter, and Saturn’s Titan. All Saturn’s smaller moons are too small and faint and lost in twilight by now. The pair of planets will soon be setting, so set up early to catch them as high in the sky as you can. This approximates the upright view at about 6 p.m. CST with 100X with a telescope, the closest conjunction of these two planets since 1623.

Faster moving Jupiter moves on, and both are getting lost in the sun’s glare by New Years. The first quarter moon is Dec. 21, which is also the winter solstice, our shortest day. Winter begins at 4:02 a.m. CST. On Dec. 23, the waxing gibbous moon passes six degrees north of fading red Mars in the SE. The Full Moon, the Yule or Long Night Moon, is on Dec. 30.

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. Visit skymaps.com for a more extensive calendar, and list of best objects for the naked eyes, binoculars, and scopes on the back of the map.

The square of Pegasus dominates the western sky. South of it are the watery constellations of Pisces (the fish), Capricorn (Sea Goat), Aquarius (the Water Bearer), and Cetus (the Whale). Below Aquarius is Fomalhaut, the only first magnitude star of the southern fall sky. It is the mouth of Pisces Australius, the Southern Fish.

Mars is currently in Pisces, but will over eastward into Aries by month’s end. The constellation Cassiopeia contains many nice star clusters for binocular users in her outer arm of our Milky Way, extending to the northeast now. Her daughter, Andromeda, starts with the northeast corner star of Pegasus’ Square, and goes northeast 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 west 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. 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 Pleiades, but about half their distance. Their appearance in November in classical times was associated with the stormy season, when frail sailing ships stayed in port. Aldeberan is not a member of the Hyades, but about twice as close as the Hyades; distances in astronomy can be deceiving. 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). 

The Great Nebula of Orion is an outstanding binocular and telescopic stellar nursery. It is part of a huge spiral arm gas cloud, with active starbirth all over the place.  EAAA member Marc Glover took this portrait in November with just a 80mm refractor.Credit EAAA Member Marc GloverEdit | Remove

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. 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 southeast sky by 7 p.m., 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 eight 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.

Over the winter, the Escambia Amateur Astronomers Association works with the Florida State parks to host deep sky gazes at Big Lagoon State Park on the Saturdays closest to the first and third quarter moons. These will include Dec. 5 and 19, and to start 2021, Jan. 2, 16, and 30. We will announce our beach gaze schedule for next year in the spring. For more info, contact gaze coordinator Dewey Barker at 450-7767 or EAAA President Ed Magowan at 287-1187. For more information on the Escambia Amateur Astronomers, visit eaaa.net or join us on Facebook.