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This is the Griffith Observatory Sky Report through December 5th, 2018. Here’s what’s happening in the skies of southern California.
Only a few more days remain this year to see Saturn in the evening twilight. At 5:30 p.m., when the sky should be dark enough to see it, Saturn appears similar to a solitary, bright golden star low in the southwest sky. Its elevation above the horizon at 5:30 p.m. decreases from 13 degrees on November 8th to seven degrees on December 5th.
The orange planet Mars is in the faint constellation Aquarius the Water-Bearer, is at its highest and crossing the meridian in the southern sky at 5:30 p.m. At that time, directly below Mars and midway between the planet and the horizon, the bright star Fomalhaut, in the constellation Pisces Austrinus the Southern Fishes, glimmers with a blue-white hue. Mars sets below the west-southwest horizon at 11:34 p.m.
The brightest planet, Venus, blazes in the southeast sky before sunrise. It appears as the third brightest astronomical object after the sun and moon.
The moon wanes from gibbous to last quarter on November 29th, and afterwards it is crescent until it becomes new on December 6th. The time of moonrise occurs nearly an hour later from one night to the next. As a result, it rises at 10:42 p.m. on November 28th and at 6:00 a.m. on December 5th. The crescent moon poses above Venus on December 3rd.
With the moon out of the early evening sky, conditions are ideal for observing the brightening comet 46P/Wirtanen, now approaching its 7-million mile close approach of Earth on December 16th. The comet is best observed from wilderness locations, far from the glow of urban light pollution. It crosses the meridian to the south at about 9:45 p.m. The comet is in the part of the sky between Mars and the lower stars of Orion the Hunter through December 6th. It is travelling northward against the background of stars and it crosses from the constellation Cetus the Sea Monster to Eridanus the River on the 24th. The comet is bright enough to see by the unaided eye, although binoculars and telescopes will greatly improve the view. It will appear as a round, luminous cloud, similar in diameter to the moon. Comet Wirtanen is distinctly green in photographs. If you can take time exposures, it should be easy to record the comet with DSLR cameras and even with some smart phones! Detailed observing information and star charts for comet Wirtanen are available on the Sky and Telescope webpage.
Free views of the Sun during the day and of the moon, planets, and other celestial objects at night are available to the public in clear weather through Griffith Observatory’s telescopes from Tuesday through Sunday, before 9:30 p.m. Check our website for the schedule. The next free public star party on the grounds of Griffith Observatory, hosted by the Los Angeles Astronomical Society, the Sidewalk Astronomers, and the Planetary Society, will take place on Saturday, December 15th.
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From Griffith Observatory, I’m Anthony Cook, and I can be reached at griffithobserver@gmail.com.