Messier 81 is the largest galaxy in the M81 Group, a group of 34 galaxies located in the constellation Ursa Major.[19] The distance from the Earth to the group is approximately 11.7 Mly (3.6 Mpc), making this one of the closest groups to the Local Group, which contains the Milky Way.[19]
M81 is gravitationally interacting with Messier 82 and NGC 3077.[20] The interactions have stripped some hydrogen gas away from all three galaxies, leading to the formation of filamentary gas structures in the group.[20] Moreover, the interactions have also caused some interstellar gas to fall into the centers of Messier 82 and NGC 3077, which has led to strong starburst activity (or the formation of many stars) within the centers of these two galaxies.[20]
Messier 81 is located approximately 10° northwest of Alpha Ursae Majoris along with several other galaxies in the Messier 81 Group.[6][21] Messier 81 and Messier 82 can both be viewed easily using binoculars and small telescopes.[21][6] The two objects are generally not observable to the unaided eye, although highly experienced amateur astronomers may be able to see Messier 81 under exceptional observing conditions.[6] Telescopes with apertures of 8 inches or larger are needed to distinguish structure in the galaxy