Messier 81 is a spiral galaxy about 12 million light-years away, with a diameter of 90,000 light years, about half the size of the Milky Way, in the constellation Ursa Major. Due to its proximity to Earth, large size, and active galactic nucleus, Messier 81 has been studied extensively by professional astronomers.

Distance to Earth: 11.74 million light years

Radius: 45,000 light years

Age: 13.31 billion years

Apparent size (V): 26.9 × 14.1 moa

Coordinates: RA 9h 55m 33s | Dec +69° 3′ 55″

Did you know: M82 is one of two galaxies strongly influenced gravitationally by M81.