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This is the Griffith Observatory Sky Report through December 16, 2015. Here’s what’s happening in the skies of southern California.
The annual Geminid meteor shower reaches its peak Sunday night and early Monday morning, December 13 through 14. The meteors can be seen as early as 7:00 p.m., and continue until dawn. Geminid meteors appear in the greatest numbers when the point from which they appear to stream, the radiant, is overhead. The Geminid radiant, near the bright star Castor of the constellation Gemini the Twins, is directly overhead at 1:53 a.m. From a dark mountain or desert wilderness location–free from light pollution–you might see up to 120 Geminid meteors per hour. Even if you can’t be up late or travel to an ideal site, the Geminid meteor shower can put on a worthwhile show from a more casual backyard setting as early as 10:00-11:00 p.m. The meteors at that time will appear to come from the east, at the rate of one every few minutes. Please note that Griffith Park closes at 10:00 p.m. and will not be open late for meteor watching.
The moon is new on the morning of the 11th. It reappears as waning crescent about half an hour after sunset on Sunday the 12th, when it will be ten degrees above the southwest horizon. Ten degrees is about the same angle that your clenched fist spans when it is viewed from arm’s length. The time of moonset advances from 6:20 p.m. on the 12th to 10:24 p.m. on the 16th.
The second brightest planet, Jupiter, in the constellation Leo the Lion, rises above the eastern horizon before midnight, and is 60 degrees high in the south at dawn. Use a telescope to see the planet’s banded cloud features and four large moons.
Orange planet Mars, in the constellation Virgo the Maiden, rises above the east-southeast horizon before 2:00 a.m. The planet is best seen just before dawn, when it is 42 degrees high in the southeast. Mars currently appears close to Virgo’s brightest star, Spica.
The brightest planet, Venus rises in the east-southeast at 3:30 a.m. Venus is 30 degrees high in the southeast at dawn, and is bright enough to see after sunrise.
Before dawn starts at 5:20 a.m., Venus and Mars can guide you to comet Catalina, C/2013 US10, currently magnitude 6.2 and visible in binoculars. On Thursday the 10th, comet Catalina is 6 degrees (about one binocular field-of-view) to the upper left of Venus. On following mornings, the comet appears a little farther from and more directly above Venus. By Wednesday the 16th, comet Catalina will be 15 degrees above Venus and 16 degrees to the left of Mars. The comet is closest to Earth, 66.2 million miles away, on the 12th. Detailed observing charts and other information about comet Catalina are available on a special Sky and Telescope Webpage.
After having been hidden for several weeks by the sun’s glare, the ringed planet Saturn returns to visibility in the morning sky on the 13th. Saturn will then appear as a golden point of light about 5 degrees above the east-southeast horizon at 6:21 a.m., the start of civil twilight. Binoculars will help you to see Saturn against the dawn’s brightness. Located in the constellation Ophiuchus the Serpent Bearer, Saturn will become much easier to see in coming weeks.
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 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 19.
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From Griffith Observatory, I’m Anthony Cook and I can be reached at griffithobserver@gmail.com