Photo of the Week for July 18, 2014
The giant spiral galaxy M101, known as the Pinwheel Galaxy, is located near the end of the Big Dipper’s handle. With a diameter of about 170 thousand light-years, M101 is larger than our galaxy. It is about 25 million light-years distant. The pinkish regions in the spiral arms are star-birth nebulas.
Observing the spiral-arm structures seen in this detailed image by Brian McGaffney requires a very large telescope. McGaffney used a 17-inch scope equipped with a Alta U16M CCD camera for this image, captured at his observatory south of Bancroft, Ontario. The image utilizes a total exposure of around 14 hours acquired over five nights.