• Tonight's chart shows Polaris and the Big and Little Dippers for a September evening. You can use the Big Dipper to find Polaris, which is also known as the North Star. Notice that a line from the two outermost stars in the bowl of the Big Dipper points to Polaris. And notice that Polaris marks the tip of the handle of the Little Dipper.
• 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.
• The Big and Little Dippers: All you need to know
• The Big Dipper swings full circle - 360 degrees - around Polaris in about 23 hours and 56 minutes. In 24 hours, the Big Dipper actually swings more than full circle, or 361 degrees. Does that make a difference? Yes! It means that - if you look at the same time each evening - the Big Dipper will appear just a little bit lower in the northwestern evening sky.
• If you're in the northern U.S., Canada or at a similar latitude, the Big Dipper is circumpolar for you - always above the horizon.
• A month from now at mid-evening, the Big Dipper will be noticeably lower in the northwest. It'll actually beneath the horizon as seen from the southern latitudes in the United States - although it's circumpolar, or always above the northern horizon, as seen from the northern U.S., Canada and similarly northern latitudes.

(Continued on page 14)