Messier 81 is a spiral galaxy located in the constellation Ursa Major.

Discovered in 1774 by Johan Elert Bode, the galaxy is also known as “Bode’s Galaxy” or NGC3031.
It lies at a distance of approximately 12 million light years.

M81 is the largest galaxy in the so called M81 Group, containing 34 galaxies, all in the constellation Ursa Major.
The small and faint patch to the north of the galaxy is called Homlberg IX. This is a dwarf irregular galaxy and a satellite galaxy of M81.

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Image data

Object info
Name M81 – Bode’s Galaxy
Type Spiral galaxy
Constellation Ursa Major
Right ascension 09h 55m 33s
Declination +69° 03′ 55″
Distance 12 Mly
Other designations NGC3031, UGC5318, PGC28630
Image info
Image date Mar. 19, 2012
Light frames 8x 4 min. RGB (each) unbinned, 16x 4 min. UHC-S unbinned (Luminance)
Total integration 2h 40m
Dark frames 10x
Flat frames 10x p. filter unbinned. Created with an A3 size Posterpoweruk flatfield panel
Bias frames 10x
Software used CCDOps, CCDSoft, ImagesPlus, PixInsight LE, Photoshop CS4
Processing CCDOPS was used for focussing. Image Acquisition was done using CCDSoft.
All separate frames were calibrated, aligned and stacked in ImagesPlus 2.8.
PixInsight LE was used for DBE, Photoshop CS4 was used for further processing – curves adjustment, levels adjustment, etc.
Noel Carboni’s toolset was used as well (Local Contrast Enhancement, Deep Space Noise Reduction)
(L)RGB combine was done in Photoshop.
Equipment info
Telescope Orion Optics SPX 10″ Newton
Corrector Televue 2″ Paracorr coma corrector (FL: 1.380mm f/5.43)
Mount Losmandy G-11 Gemini
Camera SBIG ST-8300M
Guide camera Atik 1HS Mono
Guide scope Celestron 60/700 Achromat
Autoguide software PHD Guiding
Filters Baader 2″ RGB + IDAS LPS-P2
Location Landgraaf, The Netherlands
Image comments

Distance from Paracorr to CCD is not correct.