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This is the Griffith Observatory Sky Report through December 6, 2017. Here’s what’s happening in the skies of southern California.
The moon is bright nearly all of the night time hours through the 6th. It waxes from gibbous to full moon on the 3rd, and on the following nights it is waning gibbous. The full moon on the 3rd coincides with its passage through the closest point of its elliptical orbit to the earth, its perigee, which is about seven percent closer than its average distance. It will then be 222,000 miles away as compared to its average distance, 238,000 miles. This perigee full moon, known popularly as a “supermoon,” will rise above the east-northeastern horizon, as seen from Los Angeles, at 5:18 p.m.
On the evenings up to December 4th, you have a chance to see the innermost planet, Mercury, and the ringed planet, Saturn. They can be seen only between 5:15 and 5:30 p.m., when the sky is dark enough, but before they are too close to the horizon. Mercury appears star-like against the bright glow of twilight at 5:15 p.m. It appears closer to the horizon on successive nights through December 3rd, as its elevation drops from seven degrees to five degrees over this period. Saturn appears less than three degrees to the right of, and slightly higher than Mercury through the 3rd. On the following evening, both planets will be lost in the sun’s glare and hidden from our view until they reappear in the morning sky, weeks later.
Magnification is needed to find the outermost planets, Uranus and Neptune. Uranus is in the constellation Aquarius the Water-Bearer and Neptune is in the adjacent constellation, Pisces the Fishes. Both are best seen as soon as darkness falls. Uranus is bright enough to spot through binoculars, while Neptune requires at least a slightly larger telescope in order to find it. Both planets require high magnification to see the round disk of each planet. The planets can be found with the aid of the finder map linked to the Sky and Telescope Magazine webpage dedicated to observing them.
The brilliant planet Jupiter, appearing against the backdrop of stars forming the constellation Virgo the Maiden, is easy to see above the southeastern horizon at 5:00 a.m. Virgo’s brightest star, Spica, sparkles to the upper right of Jupiter. Near Spica, you can also see the orange-hued planet Mars. Mars will appear to the left of Spica on November 30th, and it will appear below Spica until it is nearly between Spica and Jupiter by December 5th.
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 16th.
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From Griffith Observatory, I’m Anthony Cook, and I can be reached at griffithobserver@gmail.com.