Myriad planets line up in the evening sky this month. Venus continues its run as the Evening Star, shining brightest early in the month. Much fainter Saturn stands to the upper left of Venus, with bright Jupiter, the second-brightest pinpoint in the night sky, about the same distance to the upper left of Saturn. Mercury pops into view late in the month, close to Venus.
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In the Sky This Month
December 22: Betelgeuse
Betelgeuse, the shoulder of Orion, normally is the 10th-brightest star in the night sky. In late 2019 and early 2020, though, it dropped out of the top 20. It expelled a huge cloud of gas, which cooled and condensed, blocking part of the star’s light.
December 23: Moon and Regulus
The Moon is about three-quarters full tonight, so it’s nice and bright. And it has a bright companion: Regulus, the heart of the lion. They climb into view in late evening and soar high overhead later on.
December 24: Holiday Skies
The night sky offers a few gifts to everyone tonight. As darkness falls, the planets Jupiter, Saturn, and Venus are in the southwest, from top left to bottom right. Venus is the brilliant “evening star.” The Moon heaves into view by 11 or 11:30 p.m.
December 25: Northern Cross
Look to the northwest after nightfall this evening for the Northern Cross, a grouping of stars in the constellation Cygnus, the swan. As it begins to set, a few hours after sunset, the cross stands upright, as though it were anchored to the horizon.
December 26: Algol
Many stars have great names. One of the best is Ra’s al-Ghul, better known as Algol, “the head of the ghoul” or the demon star. It represents Medusa, a monster from Greek mythology. The star is high in the east-northeast as night falls, in Perseus the hero.
December 27: Moon and Spica
Spica, the brightest star of the constellation Virgo, will stand close to the right or lower right of the Moon at dawn tomorrow.
December 28: Horsehead Nebula
The Horsehead Nebula, in the constellation Orion, is visible through telescopes. It consists of a bright pink cloud of hydrogen gas with a dark cloud of cold dust in front of it. Part of the dust cloud forms the silhouette of a horse’s head.
New December 4, 1:43 am
First December 10, 7:36 pm
Full December 18, 10:35 pm
Last December 26, 8:24 pm
Times are U.S. Central Time.
Perigee December 4
Apogee December 17
The full Moon of December is known as the Long Night Moon or Moon Before Yule.