Polaris and the Big and Little Dippers
Discuss Print Me Email to FriendTonight is Sunday, Sep 07 2008
Tonight’s chart shows the Big Dipper for around mid evening. Notice that a line from the two outermost stars in the bowl of the Big Dipper point to Polaris, the North Star. And notice that Polaris marks the tip of the handle of the Little Dipper.
Compare this chart to the chart from August 2, and note that the Big Dipper is lower in the northwest in the evening now than it was a month ago. A month from now at mid evening, the Big Dipper will be lower yet in the northern sky, even sinking beneath the horizon as seen from the southern latitudes in the United States.
The constant motion from night to night, of these stars circling Polaris, is a bit like a bear circling its prey, looking for a way to attack. Several ancient cultures from the Greeks and Romans to the Micmac Indians likened these stars to a bear. In Greek myth, the Big Dipper asterism represents the hindquarters and tail of the constellation Ursa Major, the Great Bear. The Micmacs saw the three stars of the Big Dipper handle as hunters chasing the bear.
The northern sky is a large clock, with Polaris at its center. The hour hand is a line drawn through Dubhe and Merak, the two pointer stars of the Big Dipper. Because the stars make a full circle in 23 hours 56 minutes instead of exactly 24 hours, this star clock is not exactly the same as the one on the wall, but with a little practice you can learn to read it well.
