Winter Night Sky (Northern Hemisphere)

Pegasus and Andromeda sink into the west after December.  The Big Dipper lies low in the northeast.  High over the southern horizon in the winter months you see the grand constellations of winter: Orion, Taurus, Auriga, Perseus, Cassiopeia, Gemini, and Canis Major.  These constellations are rich with stars and star clusters.  Overhead in January and February lies a grand octagonal collection of brilliant stars: Capella, Castor and Pollux, Procyon, Sirius, Rigel, Aldebaran, and Betelgeuse.  These stars are a spectacular sight on a dark winter night.

The sky at 9 p.m. on February 15 from 40 degrees N latitude. Click to open in a new window.

The sky at 9 p.m. on February 15 from 40 degrees N latitude. Click to open in a new window.

Orion, the Hunter, is the feature constellation this time of year in both hemispheres, and it makes a good base of operations to find other constellations.  It takes little imagination to see a hunter outlined in these stars.  Above the little line of three stars in the belt are two stars marking his shoulders.  His left shoulder is the bright orange-red star Betelgeuse.  Below his belt are two feet; the right foot is the bright blue star Rigel.  Hanging off his belt are three fainter stars.  This is the “Sword of Orion”.  Look carefully at the middle star in the Sword.  You will see it is slightly fuzzy.  In fact this middle star is not a star at all.  It is a nebula, a misty patch of glowing hydrogen gas where new stars are forming.

Follow a line from Orion’s Belt to the south and east to see find blue-white star Sirius, the brightest star in the heavens.  The star is part of the constellation Canis Major, the Big Dog.  North and slightly east of Sirius lies the star Procyon (“pro-SY-on”) in Canis Minor, the Little Dog.

The constellation Orion in the southern sky in mid winter.

The constellation Orion in the southern sky in mid winter.

Follow the belt of Orion to the northwest to find Taurus and the bright star Aldebaran.  Follow a diagonal from blue-white Rigel at the foot of Orion through orange-red Betelgeuse in his shoulder to find the stars Castor and Pollux in the constellation Gemini, the Twins.  And directly above Orion you’ll find the constellation Auriga, also set in the Milky Way.  Its bright yellow-white star Capella twinkles almost directly overhead.

By mid-February through March, look to the east.  Here you will see rising the constellation Leo once again and a few of the same stars you met in the spring sky.  At winter’s end, the Earth has nearly made a full trip around the Sun, and the cycle of stars and constellations through the year begins again.