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M81 - Bode's Galaxy (NGC 3031), type Sb, in Ursa Major

LRGB combination - spikes added (Click for a larger view 1400 x 1400 px)

 

B / W version (Click for a larger view 1400 x 1400 px)

 

Details

M81 - Bode's Galaxy (NGC 3031), type Sb, in Ursa Major

Discovered by Johann Elert Bode in 1774.

One of the brightest galaxies in the sky and similar in size to the Milky Way. Big and beautiful spiral M81 (also designated NGC 3031) lies 11.8 million light-years away in the northern constellation Ursa Major. According to Stoyan et al. (2010) its diameter is 92,000 light years. The spiral galaxy M81 forms a physical pair with its neighbor, M82, and is the brightest and probably dominant galaxy of a nearby group called M81 group. A few tens of million years ago, which is semi-recently on the cosmic time scale, a close encounter occurred between the galaxies M81 and M82. During this event, larger and more massive M81 has dramatically deformed M82 by gravitational interaction.

Right Ascension 09 : 55.6 (h:m)
Declination +69 : 04 (deg:m)
Distance 11 800 (kly)
Visual Brightness 6.9 (mag)
Apparent Dimension 21 x 10 (arc min)

Seeing: Pickering 8 rating - Good to Excellent
Optic(s): Celestron 11" Schmidt Cassegrain + TSSCKorr2" flattener @ f/8
Mount: ASA DDM85 Premium
Camera: ATIK 4000 - monochrome CCD – 2048 x 2048 px ; 16x16 mm; 7.4 µm x 7.4 µm
Filters: Astronomics L, R, G, B set, SupaSlim TrueTechnology Computerized Filter Wheel
Dates/Times: 2012-04-25
Location: Rozhen Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42"
Exposure Details:

L = 50 min, R = 50 min, G = 50 min, B = 50 min, (Bin 1), Subexposures = 10 min, Total Exposure Time - 200 min

More details: Dark and flat frames reduction
Guiding: All subexposures are unguided thanks to ASA DDM85 Premium mount
Processing:

PixInsight / PS

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All Contents copyright Velimir Popov unless otherwise noted.