Right Ascension	09 : 55.8 (h:m)
Declination	+69 : 41 (deg:m)
Distance	12000 (kly)
Visual Brightness	8.4 (mag)
Apparent Dimension	9x4 (arc min)
Discovered by	Johan Elert Bode Dec. 31st  1774

Forming a most conspicuous physical pair with its neighbor, M81 (THE showpiece galaxies for many Northern hemispherers), this galaxy is the prototype of an irregular of the second type, i.e. a "disk" irregular. Its core seems to have suffered dramatically from a semi-recent close encounter with M81, being in a heavy starburst and displaying conspicuous dark lanes. This turbulent explosive gas flow is also a strong source of radio noise, and therefore sometimes called "Ursa Major A" (strongest radio source in UMa) . In the infrared light, M82 is the brightest galaxy in the sky; it exhibits a so-called infrared excess (it is much brighter at infrared wavelengths than in the visible part of the spectrum). This behaviour can also be observed for the companion of M51, NGC 5195, and the peculiar galaxy NGC 5128 (Centaurus A). The visual appearance is that of a silvery sliver, as John Mallas decribed it.

As a member of the M81 group, M82 is 12 million light years distant.

M82 was discovered on December 31, 1774 by Johan Elert Bode together with M81; he described it as a "nebulous patch", about 0.75 deg away from M81, which "is very pale and of elongated shape," and cataloged it as No. 18 in his catalogue. Pierre Mechain independently rediscovered both galaxies as nebulous patches in August 1779 and reported them to Charles Messier, who added them to his catalog after his position measurement on February 9, 1781.