How To Explore the Winter Sky

Reprinted as seen in the January + February issue of Washington Trails Magazine, written by Jeff Acquino.

Winter’s lack of daylight is in some ways a restriction on outdoor activities, but it does provide at least one fun opportunity: the chance to enjoy great views of the night sky. Winter brings a new set of constellations to the Pacific Northwest, and cold, clear, moonless nights in the wilderness can offer some of the best chances to observe the stars all year (provided you’re dressed warmly). 

The Orion constellation above Mount St. Helens. Photo by Orion Ahrensfeld.

The most prominent constellation in the winter sky is Orion, the Hunter. To spot him, look towards the southeast for a band of three stars—this is his belt. To the upper right of the belt is Bellatrix, a bright blue star representing Orion’s left shoulder (as he is facing us), and to the left is Betelgeuse, an old, enormous orange star that indicates his right shoulder. Below the belt hangs Orion’s sword, which might appear to be a bit fuzzy. This is because two of the three stars that make up the sword aren’t actually single stars—they are blobs of gas and stars called the Trapezium and the Orion Nebula. While it’s fairly easy to notice the fuzziness of these objects with the naked eye on a clear night, a pair of binoculars will help resolve their shape and reveal more subtle details.

Nearby are Orion’s two hunting dogs, Canis Major and Canis Minor. Extend Orion’s belt to the left and look for Sirius, the head of Canis Major (the Great Dog) and the brightest star in the night sky. Directly above Betelgeuse, Orion’s right shoulder, is Procyon, the head of Canis Minor. Procyon, Sirius, and Betelgeuse together form the quasi constellation known as the Winter Triangle. If you again use Orion’s belt as a pointer and follow it to the right, you’ll find Aldebaran, another giant orange star, which is one of the brightest in the sky. Aldebaran appears to be following a cluster of stars—the Pleiades, or the Seven Sisters, after a Native American legend of young women who climbed into the sky to avoid angry bears. Pleiades is a good test of how clear the observing conditions are. Six stars are usually visible to the eye, but on a very clear night you might be able to pick out 9, and up to 14 with binoculars.

Plan on being in a dark place (and hope for clear skies) on December 10, 2011 when a total lunar eclipse will happen near the middle of the night over the western U.S. (This will be the second of two total lunar eclipses in 2011. The first will take place on June 15.) During this event, the Earth will pass between the moon and the sun, allowing observers to watch Earth’s shadow block out the Moon for about an hour and 14 minutes.

The Pacific Northwest’s infamous winter darkness has its disadvantages, but it’s a boon for star gazing.  Camping out will give you a break from light pollution, so it is the perfect opportunity to study the night sky.

Jeff Acquino is a recent graduate of the museum studies program at the University of Washington.