M81

From South Dublin Astronomical Society

M81
Type	Spiral Galaxy
NGC	NGC 3031
Constellation	Ursa Major
Right Ascension	9h 55.6m
Declination	+69° 04'
Magnitude	6.8
Size	26 x 14 arc min.
Photo: Dave Grennan

M81 and M82 are part of one of the nearest groups of galaxies to our own Local Group at “only” 12 million light years away. One, M 81, is a large spiral tilted almost face-on to us and showing a brilliant nucleus with tightly wound arms. M 82 shows very unusual structure in detailed photographs and is now believed to be going through a huge phase of star formation. This is probably the result of a close encounter between the two galaxies — they presently lie just 150,000 light years from each other. The handiest way to find the galaxies is to take-off from Alpha (α) Ursae Majoris to 23 UMa, 10½° a little north of west. From here, go 6½º to the northeast and you’ll be in the right region. M81 is probably easiest to spot as it appears like a magnitude 7 “star” in smaller binoculars. Pushing up the magnification will let you see it as a pale oval-shaped glow. Just half a degree to it’s north, with larger binoculars, you should spot M82 as a thin spike of ghostly light.