Starwatch: Great time to view Big, Little dippers

Published 11:01 am Monday, August 16, 2010

This is a really great time to check out the famous Big and Little Dippers. I don’t have to tell you what the Big Dipper looks like. You learned that at your mother’s knee.

Right now in the early evening you can easily see the Big Dipper hanging by its handle in the northwestern sky even in areas of heavy city lighting.

This time of year the Little Dipper is standing on its handle in the northern sky after evening twilight, just to the upper right of the Big Dipper. It’s not nearly as bright as its big brother. To easily see it you really have to be away from city lights, but you should at least be able to see part of it using the Big Dipper.

Draw a line with your mind’s eye between to the two stars Merak and Dubhe found on the side of the pot section of the Big Dipper opposite the handle side. Then extend that line beyond Dubhe and use it as a pointer to find Polaris, the North Star.

Hold your clenched fist at arm’s length and extend that line three fist widths to reach Polaris. It should be easy to find since it’s the brightest star in that immediate neighborhood.

Polaris is what I call the lynchpin of the night sky, because every single star, including the sun and moon, appears to revolve around it every 24 hours.

Polaris also marks the end of the handle of the Little Dipper and is the brightest star in the Little Dipper. If you’re viewing the sky from heavy city lighting, look for the next two closest stars you can see to the upper left of the North Star.

Those two little shiners that aren’t quite as bright as Polaris are Kochab and Pherkad. They mark the side of the Little Dipper’s pot section opposite its handle. In darker skies you can easily see the two other pot stars, and two other fainter handle stars that lead up to Polaris.

Did you know that the Big Dipper is not an official constellation? Back in the 1930s astronomers from all around the world agreed on a standard set of 88 constellations and the Big Dipper wasn’t one of them.

The astronomers call it an asterism, a distinct pattern of stars, a step below a constellation. You would think the most famous star pattern would rate the title of constellation, but it’s just an asterism.

The Big Dipper is actually the rear end and tail of the official constellation Ursa Major, the Big Bear. It’s the brightest part of the Big Bear, and this time of year you should be able to see the rest of the bear with just a little bit of work, a semi-dark sky and a comfortable lawn chair to lie back on.

Look just to the lower right of the pot section of the Big Dipper for three dimmer stars forming a skinny triangle that outlines the Big Bear’s head. That’s the dimmest part of the Big Bear. From that skinny triangle, look to the lower right for two stars right next to each other that should jump right out at you. These are Talitha and Al Kapra, and they mark the position of the bear’s front paw.

Between the front paw stars and the triangular head is a star that makes up the bear’s knee, and once you spot that, you’ve seen one of the front legs of Ursa Major. There are no stars that make up the other front leg.

Two curved lines of stars outline the bear’s back legs, and the one in the foreground is much easier to see. Just look to the upper left of the two front paw stars Talitha and Al Kapra for two more stars right next to each other. Those are Tanis Borealis and Tanis Australis, the back paw of the Big Bear.

To see the rear leg, look for a line of stars to the upper left of the rear paw that bends to the upper right and joins the rear end of the pot section of the Big Dipper (or the rear end of the Big Bear).

The seven stars that make up the Little Dipper are the same seven that outline the Little Bear, otherwise known as Ursa Minor. Polaris marks the end of the Little Bear’s tail.

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 at www.everettastro.org/