Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light years away in the constellation Ursa Major. It has a diameter of 96,000 light years. Because of its relative proximity to the Milky Way galaxy, large size, and active galactic nucleus which harbours a 70 million super massive black hole, Messier 81 has been studied extensively by professional astronomers.