December 15, 2014
These free, printable Sky Maps (star charts) by astrononer Jeff DeTray will help find your way around the night sky!
Each month, Jeff’s Sky Maps highlight a wonderful event in the evening sky—including beautiful stars, constellations, planets, conjuntions with the Moon, meteor showers, and other amazing celestial objects.
Sky Map January 2015
By Jeff DeTray, Almanac astronomer writer
Follow Jeff DeTray’s sky adventures at AstronomyBoy.com
The Brightest Nights of the Year
Just click, print, and bring outside!
When you look to the east on January evenings, you see a sky that is absolutely ablaze with bright stars. Coupled with the crisp, clear air of midwinter, it’s often the brightest night sky that you’ll see all year.
Both astronomers and casual sky gazers look for patterns in the stars. Easy-to-see patterns help us to find our way around the sky, and the bright stars of winter do a wonderful job of helping us to get our bearings. Our first and smallest star pattern lies within the constellation Orion, the Hunter.
On January evenings, Orion is in the east and appears from our point of view to be reclining. Due to this recumbent posture, the three bright stars that form Orion’s Belt lie in a vertical line that is easily recognized. Orion’s Belt is an example of an asterism, a distinctive pattern of stars that is not one of the 88 official constellations. Asterisms come in all shapes and sizes and are small groupings of stars within constellations. Another example at the far left edge of this month’s map is the Big Dipper, an asterism that lies within the much larger constellation Ursa Major, the Greater Bear.
Sky map produced using Chris Marriott’s Skymap Pro
Once you have spotted Orion’s Belt, you should be able to recognize Orion himself, our second pattern of the night. Orion is the brightest of all constellations, and in addition to its Belt, it contains two very bright stars.
The one on the left is Betelgeuse, a red giant star that looks slightly orange-ish to our unaided eyes. To the right lies Rigel, a shining white star. Comparing the orangey hue of Betelgeuse to the pure white of Rigel is an opportunity to see that stars really do come in different colors. Star colors are easiest to see when the stars are bright, and these two are among the sky’s 10 brightest.
Betelgeuse is at one corner of our third star pattern, the Winter Triangle, marked in green on our Sky Map. Look downward to the left and right of Betelgeuse to see two more bright stars. These are Procyon on the left and Sirius on the right. Together with Betelgeuse they form a nearly equilateral triangle, a triangle with three sides of equal length. Sirius is the brightest star in the sky, and Procyon ranks in the top 10 as well. The Winter Triangle spans multiple constellations, including parts of Orion, Canis Major (Greater Dog), Canis Minor (Lesser Dog), and Monoceros (Unicorn).
Rigel, Sirius, and Procyon form a part of our fourth and largest star pattern, the Winter Circle (or Oval or Hexagon, take your pick), outlined in purple. Starting from Rigel and moving clockwise, this big pattern includes Sirius, Procyon, Castor and Pollux (the Gemini Twins), Capella, and Aldebaran. All seven stars are among the 25 brightest in the sky, making the Winter Circle easy to see, once you know to look for it. Aldebaran, in the constellation Taurus, the Bull, is another noticeably orange-ish star, especially when compared to obviously white stars such as Capella and Rigel.
Two more celestial sights on this month’s map are worth noting. Just rising above the horizon on our map is the giant planet Jupiter. The planet will rise higher as the night wears on and is currently very bright. Toward the top of the map above Aldebaran lies the Pleiades star cluster. If your vision is sharp enough, you may be able to see a handful of individual stars at that location. Many of us, however, can’t resolve the Pleiades into individual stars and see only a bright, hazy blob.
See our Sky Watch page for more highlights of the monthly sky, courtesy of The Old Farmer’s Almanac.