By Bruce McClure
Earth Sky Communications
Saturday July 11, 2009
Today our star-hopping adventure begins at the Big Dipper in the constellation Ursa Major. Draw a line through the Big Dipper’s pointer stars — Duhbe and Merak — to locate Polaris the North Star.
Polaris isn’t the brightest star in the sky as commonly supposed. It’s only the 50th brightest star. Still, Polaris is bright enough to be seen with relative ease on a dark, clear night. This star is famous not for its brightness but for its location in our sky. It’s located above the Earth’s northern axis. Thus the entire northern sky appears to turn around Polaris.
Polaris is noteworthy for another reason. It makes the end of the handle on the Little Dipper asterism, in the constellation Ursa Minor. An asterism is not a whole constellation. It’s a noticeable pattern with in a constellation.
As night deepens, and that fainter starts of the Little Dipper spring into view, those of you with dark-enough skies can expect to see a winding stream of stars between the Big and Little Dippers. What is this stream of starts between the Dippers? The star Thuban is one of the stars here, part f the Tail of the legendary constellation Draco the Dragon, a fixture of the northern skies. For more about Draco, see tomorrow’s sky chart.