Messier 81 (also known as NGC 3031 or Bode’s Galaxy) is a grand design spiral galaxy about 12 million light-years away, with a diameter of 90,000 light years, in the constellation Ursa Major. Due to its proximity to our galaxy, large size, and active galactic nucleus (which harbors a 70 million M_☉supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy’s large size and relatively high brightness also makes it a popular target for amateur astronomers.

M81 (left) and M82 (right). M82 is one of two galaxies strongly influenced gravitationally by M81. The other, NGC 3077, is located off the top edge of this image.