These are a fascinating pair of interacting galaxies, which, in my opinion, are best viewed together. I would like some further integration time for the image below, but I think its ready for a first cut.
The image comprises exposures with both a 40D & a modified 300D, to use the capabilities of both.
M81 (right) is a classic spiral galaxy, somewhat similar in size to our own Milky Way. It is located in Ursa Major at a distance of some 12 million light years from ourselves. The galaxy’s core is most likely centred upon a super massive black hole.
M82 (left) is a curious & extremely active galaxy. It was, until recently, thought to have an irregular structure but it is now discovered to have 2 feint spiral arms. M82, the Cigar galaxy, is in strong gravitational interaction with M81. This interaction has caused huge upheaval in the galactic core, resulting in great star formation activity & the expulsion of clouds of dust & gas.
The image above has detected some of their extent, in the far red & infra-red spectrum; for a wider spectrum view, look at this amazing image produced by using Hubble, Chandra & Spitzer together. This extreme activity is also the cause of M82 being an extremely bright source of radio waves.
Both galaxies were discovered by Johann Bode in 1774 and then re-found in 1779 by Pierre Mechain, who added them to Messier’s list.