Messier 81, also known as NGC 3031 is a spiral galaxy. It is the largest of a group of 34 galaxies in Ursa Major, including its near neighbor M82, ‘merely’ 300,ooo light-years away. Some scientists believe that the high rate of star formation in M82 was caused by a close encounter with M81 some 500 million years ago which stirred up a lot of dust and gas in the neighboring galaxy.
This image was taken with a Canon 6D camera attached to a Takahashi Mewlon 250 telescope at f/12. Fifty-three frames of 2-minute exposures were combined, for a total exposure of 1 hr 46 minutes. DeepSkyStacker v 3.3.2 and Photoshop CC with Astronomy Tools from ProDigital Software were used to enhance the structure of the spiral arms.