M 81 Bode's Galaxy

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About this Image

The pronounced grand-design spiral galaxy M 81 forms a most conspicuous physical pair with its neighbor, M82, and is the brightest and probably dominant galaxy of a nearby group called M 81 group.
A few tens of million years ago, which is semi-recently on the cosmic time scale, a close encounter occurred between the galaxies M 81 and M 82. During this event, larger and more massive M 81 has dramatically deformed M 82 by gravitational interaction. The encounter has also left traces in the spiral pattern of the brighter and larger galaxy M 81, first making it overall more pronounced, and second in the form of the dark linear features (below the center) of the nuclear region.

The galaxies are still close together, their centers separated by a linear distance of only about 150,000 light years. The M 81 in Ursa Major is situated 12 million light years away.

Above M 81 there is the faint blue companion galaxy Holmberg IX visible.

North is right

 


Technical Details
Optics

16" cassegrain at F/10 (L) and at f/3 (color)

Mount MK-100 GEM
Camera SBIG STL-11000M at -30C, internal filter wheel
Filters Astronomik LRGB + H-alpha
Date Color:Jan 14, 2005.
Luminance: Nov 2005 - Jan 2006
Location Wildon/Austria
Sky Conditions mag 5 sky, changing transparency and seeing, temperature -5 - 0 C
Exposure Luminance at f/10 = 180 min (10 min subexposures)
R:G:B at F/3 = 30:30:30 minutes (5-minute sub-exposures),
30 min Halpha at F/3 (10-minute sub-exposures),
Processing Image aquisition in Maxim, image calibration, aligning, DDP in ImagesPlus; H-alpha added to red; color balance, curves in Photoshop;
north is to the right;