Galaxy Pair M81/M82 Bright Galaxies in Ursa Major

Uploaded 4/19/10

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 There are few pairs of galaxies in the sky as spectacular as these two, and both fit very well in the 1.5 degree field of my 8" Astrograph. On the left is M81, a 7.9th magnitude inclined spiral spanning 27 arcminutes in width. You can clearly see the yellow core surrounded by the blue spiral arms here.

On the right is the peculiar active galaxy M82, 9.3rd magnitude and spanning some 11 arc minutes long. Its nearly edge on, only inclined 7 degrees from our line of sight. The warped ends of its disk from the gravitational tug of M81 can be seen even at this scale, and the core is awash in red hydrogen from its active quasar like nucleus.

There are dozens of faint background images in this image, a notable object is just above the core of M81, this blue nearly resolved object is UGC5336 (Holmberg IX) which is a Magellenic type galaxy companion to this host galaxy and is 14th magnitude.

Along the right edge of M81 and along the bottom you can just see some wispy nebulosity. This is the so called "Galactic Cirrus" or "Integrated Flux Nebula". This is simply dust high above the Milky Way galaxy that is reflecting the light of the entire galaxies disk. It is extremely faint, and in this part of the sky extends from Polaris the north star to this part of the sky in a long ribbon.

The stunning orange K0 star at the lower right is 7.2 magnitude and has a B-V index of 1.2.

Optics: 8" f/4 Newtonian Astrograph w/Baader MPCC Coma Corrector Platform: Astrophysics AP1200 Camera: Hutech Modified Canon XTi @ ISO800 Exposure: 24 x 5m = 2h Location: Payson, Arizona Elevation: 5150 ft. Sky: Seeing 7/10, Transparency 8/10 Outside Temperature: 45F Processing Tools: Photoshop CS2, Images Plus 3.82 HOME GALAXIES EMISSION NEBS REFLECTION NEBS COMETS GLOBULARS OPEN CLUST PLANETARIES LINKS