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By Deane Morrison

     The dark skies of December form a fitting backdrop for the interplay of the moon and planets and the arrival of the iconic winter stars. 

In the first half of the month, no moon will interfere with views of the early evening sky. In the west, Saturn drops as Earth leaves it behind in the orbital race, but it will always be up at nightfall. So will Jupiter, a beacon in the eastern sky. 

East of Jupiter, two famous star clusters herald winter’s approach. About midway between Jupiter and Capella—the bright star in the northeast—you’ll see the Pleiades cluster. The Pleiades are only about 100 million years old, compared to some 4.5 billion years for our sun. The cluster’s thousand-plus stars formed in the same stellar nursery and are approximately 445 light-years away.

Below the Pleiades is the V-shaped Hyades cluster, which forms the face of Taurus, the bull. A mere 150 light-years away, it’s the closest star cluster to Earth. The bull’s eye is the bright star Aldebaran, which is closer than the Hyades and not part of the cluster. 

December’s full moon rises about 45 minutes before sunset on the 26th. It travels the night sky amid the large knot of bright winter constellations, near the left leg of the Gemini twin Castor.

In the morning sky, on the 1st brilliant Venus appears in the southeast close to Spica, the brightest star in Virgo, the maiden. But the two quickly separate as Venus sinks and Spica soars. A waning moon visits Spica on the 8th and Venus the 9th. The bright star to the upper left of the pair is Arcturus, in Bootes, the herdsman. 

Winter begins with the solstice, at 9:27 p.m. on the 21st. At that moment, the sun reaches a point over the Tropic of Capricorn and begins its long journey back north.  

The University of Minnesota offers public viewings of the night sky at its Duluth and Twin Cities campuses. For more information, see:

• Duluth, Marshall W. Alworth Planetarium: www.d.umn.edu/planet

• Twin Cities, Minnesota Institute for Astrophysics: www.astro.umn.edu/outreach/pubnight

• Check out astronomy programs, free telescope events, and planetarium shows at the

• University of Minnesota’s Bell Museum: www.bellmuseum.umn.edu/astronomy

• Find U of M astronomers and links to the world of astronomy at: http://www.astro.umn.edu