It’s getting colder here in the northern hemisphere. But colder weather means brighter stars and a richer deep sky are moving into view, and they are a welcome sight after the relatively barren skies of northern autumn. Stargazers in the northern and southern hemispheres can now see the majestic constellation Orion rise in the east in the late evening. The constellation is preceded by the V-shaped head of Taurus and the lovely Pleiades star cluster. And it’s followed by the brilliant star Sirius and the constellation Canis Major. This month the Moon, as it moves along the ecliptic, points the way to the bright planets Venus, Jupiter, and Saturn. And the Geminid meteor shower, one of the best of the year, peaks mid-month. Here’s what to see in the night sky this month…
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5-6 December. In the mid-evening hours, look for the nearly full Moon tangled in the starry “horns” of the constellation Taurus, the Bull, and quite close to the bright orange star Aldebaran.
6 Dec. Full Moon, 12:27 UT (the “Cold Moon” or the “Long Nights Moon”)
8 Dec. Mercury reaches superior conjunction with the Sun and remains lost in sunlight for most of the month. But next month little Mercury will make a spectacular pairing with Venus in the evening sky.
11-12 Dec. In the pre-dawn hours, look nearly overhead for the waning gibbous Moon near the bright planet Jupiter. Both are near the “Sickle of Leo”, a reverse question-marked-shaped group of stars that makes up of the head of the constellation Leo, the Lion. Jupiter looks great in a telescope now, and it will just get better over the next few months.
13-14 Dec. The Geminid meteor shower peaks in the early-morning hours of December 14. The last-quarter Moon rises near midnight and obscures fainter meteors. So your best chance to see the Geminids may be a little before midnight on the 13th. This is one of the best meteor showers of the year. You can see Geminids anywhere in the sky and from anywhere on Earth. They will trace their path back to a point in the constellation Gemini near the star Castor. If possible, look just after dark for a few Geminids as they enter the atmosphere at a shallow angle and burn slowly across the sky.
14 Dec. Last Quarter Moon, 12:51 UT.
19 Dec. Saturn has returned to the morning sky and hovers near a slender waning crescent Moon. Look for the pair low in the southeastern sky as seen from the northern hemisphere, and also look for the brilliant red star Antares closer to the horizon. In the southern hemisphere, look for Saturn and the Moon in the east; Antares will lie to the right of the pair.
21 Dec. The Sun reaches its most southerly position on the ecliptic at 23:03 Universal Time (GMT). This marks the beginning of summer in the southern hemisphere and winter in the northern hemisphere.
22 Dec. New Moon, 01:36 UT.
22 Dec. An observing challenge… With binoculars, look for the bright planet Venus near the very slender waxing crescent Moon low in the southwestern sky after sunset (visible in the northern hemisphere only). The Moon will be a little higher on Dec. 23rd and visible more readily in both hemispheres. Venus is at a very bright magnitude -3.9, but it still lies low on the horizon in the constellation Sagittarius. It’s a little higher above the horizon for deep-southern stargazers.
24 Dec. The Moon points the way to yet another planet, this time the planet Mars. Look for crescent Moon and Mars low in the southwestern sky after sunset.
25 Dec. Merry Christmas!
28 Dec. First-Quarter Moon, 18:31 UT.