Happy Trails

This ten-minute exposure of the north sky as seen from rural Shueyville, Iowa on August 21, 2010, shows star trails created by the rotation of the Earth. The bright star that appears fixed just above the tree line at right center is Polaris, the north star. Polaris does not appear to show a "trail" because it is located just one degree from the exact pole. Polaris has not always been the pole star. 5,000 years ago it was the faint Thuban, in the constellation Draco. Gamma Cephei will take over the distinction about 1,000 years from now. Polaris is located at the end of the "handle" of the Little Dipper. This shot, began at 9:50 PM, was imaged with a focal length of 18mm at f/3.5, and an ISO rating of 400.