We’re naturally drawn to the bright and obvious in the night sky. Everyone knows Orion the hunter and many of us can find Sirius in Canis Major the Big Dog. Ditto for the Big Dipper. All this attention-grabbing leaves the lesser constellations to ply the sky with far fewer admirers. Let’s do something to correct that. We’ll start with a surprisingly easy but virtually unknown star group — at least among the general populace — called Canis Minor the Little Dog.
First, let me say that Canis Minor hardly looks like its name. Two stars comprise the entire constellation. Connect them with a line and you’ve got a bone to toss to an actual dog. Maybe. But the simplicity of the group make it easy to see and remember. Moreover, it’s super easy to find.
Go out around 8:30-9 p.m. in mid-January and face southeast. Straight off you’ll see the three stars in a row that define Orion’s Belt. Shoot an arrow through the belt down toward the horizon, and it will pierce brilliant Sirius along the way. Sirius shines about two fists below Orion. Its brilliance and twinkle are matchless.
Now, thrust your balled fist to the sky and mark off a little more than two fists to the upper left of Sirius. You’ll see a bright star there — that’s Procyon (PRO-see-on), Canis Minor’s brightest star and the 8th brightest star in the sky. I hope you’re asking yourself “where have you been all my life?” right now. How nice to finally make its acquaintance. A fainter star will catch your eye just a few degrees to the upper right of Procyon called Gomeisa. Sketch a line between them in your mind’s eye and that’s Canis Minor.
It gets better. If you now draw a line from Procyon to Betelgeuse (in Orion) and from there back down to Sirius you’ll be staring at a big, nearly-equilateral triangle. Skywatchers call it the Winter Triangle. Summer’s got one. Why not winter, right? Figures composed of easy, bright stars that are either a part of a constellation or combine stars from several constellations are called asterisms. Orion’s Belt is the most famous of them.
While you’re out admiring Canis Minor be sure to give a look at Betelgeuse. This famous red supergiant star can shine as brightly as Procyon (magnitude 0.4), but it has faded dramatically over the past two months. Click here for additional information about the star’s history-making “fainting.”
Procyon is one of Earth’s nearest neighbors at just 11.5 light years away. After the Alpha Centauri system and Sirius, the Little Dog Star is the third closest bright star in the sky. If you replaced the sun with Procyon you’d immediately regret doing so. The star is only a little hotter but twice as big, so things would heat up here in a hurry. It’s also orbited by a tiny, planet-sized companion star called a white dwarf called Procyon B. Speaking of white, Sirius appears very white to the naked eye. Compare it next time to cooler Procyon, which appears yellow in contrast, then swing over to orange-red Betelgeuse for the complete color fiesta.
The name Procyon comes from the ancient Greek “before the dog” and refers to the star rising before Sirius (a.k.a. the Dog Star) does. Let that be an acknowledgement that little dogs count too.