It’s the dogs’ turn to play in a late winter sky

Published 2:43 pm Friday, March 14, 2008

Who let the dogs out?

In the case of the celestial hounds of heaven, the constellations Canis Major and Canis Minor, you can blame Orion the Hunter for turning the doggies of heaven loose in our starry skies.

The constellation Orion is one of the best known and recognized characters in the night sky. He’s certainly the king of the cold winter heavens, surrounded by a gang of bright stars and companion constellations.

According to Greek and Roman mythology, Orion was the son of Poseidon, god of the seas. Because of his father’s genes, Orion had great size and strength that gave him a huge advantage over the beasts he hunted down.

His only weapon was his mighty club, which he would use to take out the critters he skillfully stalked. Of course, every good hunter has his faithful hunting dogs, and Orion’s best friends are his big dog, Canis Major, and his little dog, Canis Minor, which are Latin for big dog and little dog, respectively. They’re also seen as constellations adjacent to the great hunter, Orion.

Orion’s big dog, Canis Major, is easy to find. From our view, it’s just to the lower left of Orion, and as you can see it resembles a dog standing on its hind legs begging for food scraps from his master. The brightest star in the night sky, Sirius, marks the dog’s nose. Just use the three stars in a row that outline Orion’s belt as a pointer to the lower left, and you’ll run right into Sirius.

To the right of Sirius is Mirzam, a dimmer but distinct star that marks the hound’s elevated paw. To the lower left of Sirius, you can’t help but notice the triangular pattern of stars that outlines Canis Major’s hind end, hind leg and tail. As Canis Major journeys across the sky from east to west in response to Earth’s rotation, the big doggie appears to maintain its begging stance. As a matter of fact, the great poet Robert Frost takes note of this in a poem:

“Canis Major”

The great Overdog

That romps through the dark.

At either end of Canis Major are noteworthy stars. Sirius, at the nose, is not only the brightest star of the constellation, but is also the brightest star in the night sky.

Its brilliance is partially due to the fact that it’s a star larger than our sun, but is mostly because it’s so much closer than most other stars. It’s only 8 light-years away, while most other stars we see at a glance are an average of 100 light-years away. (One light-year equals almost 6 trillion miles).

At the other end of Canis Major is Aludra, the star at the end of the big dog’s tail. It’s certainly nowhere near the brilliance of Sirius, but it’s one heck of a star. Astronomers estimate that Aludra is almost a billion miles in diameter, more than 10 times the diameter of our sun. It has a reasonably humble appearance in our sky because it’s more than 3,000 light-years away. The light you see from Aludra tonight left that great star before the year 1000 B.C.

As majestic as the constellation Canis Major is, Orion’s little hunting dog, Canis Minor, is kind of a joke by comparison, at least in my opinion. It’s basically just two stars, Procyon and Gomeisa, and that’s it. It’s easy to find. Just look for the next brightest star you can see in the sky to the upper left of Sirius. That’s Procyon, the brightest star in Canis Minor. Gomeisa is a fainter star to the upper right of Procyon. How those two stars outline a dog is anybody’s guess. Maybe it’s a wiener dog.

The constellation Orion and his hunting dogs all make contributions to one of the coolest configurations in the sky, the “Winter Triangle.” In your mind’s eye, draw a line from the bright star, Betelgeuse, at the armpit of Orion the Hunter, to Sirius in Canis Major, and then up to Procyon in Canis Minor. You’ll easily see that those three bright stars make up a perfect equilateral triangle from our vantage here on Earth.

Enjoy the hounds of heaven.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, “Washington Starwatch,” available at bookstores and at his Web site www.lynchandthestars.com.

The Everett Astronomical Society welcomes new members and puts on public star parties. Their Web site is: members.tripod.com/everett_astronomy.