The Pinwheel Galaxy or Messier 101 is a face-on spiral galaxy distanced 21 million light-years away in the constellation Ursa Major. It was first discovered by Pierre Méchain on March 27, 1781.
M101 is a large galaxy comparable in size to the Milky Way. With a diameter of 170,000 light-years it is roughly equal the size of the Milky Way. It has a disk mass on the order of 100 billion solar masses, along with a small central bulge of about 3 billion solar masses.
The image was taken with 14" Newton telescope and QSI583WSG camera on a Gemini G41 mount.
Exposure times were: LRGB:7:4:3:3 hours.
All images were taken in 2x2 binning.