Minnesota Starwatch: December welcomes winter stars – Austin Daily Herald

Written by Dean Morrison

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

During the first half of the month, there is no moon to obstruct the view of the evening sky. In the west, Saturn dips when Earth is left out of the orbital race, but always rises at night. So is Jupiter, the lighthouse in the eastern sky.

To the east of Jupiter are two famous star clusters that herald the arrival of winter. The Pleiades star cluster can be seen approximately midway between Jupiter and the bright star Capella in the northeast. Our Sun is about 4.5 billion years old, while the Pleiades is only about 100 million years old. The cluster’s more than 1,000 stars are formed within the core of the same star and are approximately 445 light-years apart.

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

The full moon in December rises approximately 45 minutes before sunset on the 26th. It moves through the night sky in a large knot of bright winter constellations, near the left leg of the Castor Twins in Gemini.

In the morning sky, the brightest Venus of the day appears in the southeast near Virgo Spica, Virgo’s brightest star. However, the two soon become separated when Venus sets and Spica rises. The waning moon will visit Spica on the 8th and Venus on the 9th. The bright star in the upper left of this pair is Arcturus, the herdsman in the constellation Boes.

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

The University of Minnesota offers public viewing of the night sky on its Duluth and Twin Cities campuses. See below for more information.

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

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

• Check out our astronomy programs, free telescope events, and planetarium shows.

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

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