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M 81, together with M 82, were discovered by Johann Bode in 1774. They were rediscovered by Mechain in 1779 and included by Messier in his catalog in 1781. This is the largest (and therefore, the dominant) galaxy of the M81 Group, which includes some 34 galaxies. Bright enough to be seen with binoculars, M 81 shows nearly “perfect” spiral arms and it is a good example of what a “standard” spiral galaxy may look like. Its 12 million light years distance was calculated with the HST’s measurements of cepheid stars in it.
Additional Information
Object
Name(s): M81. NGC 3031. Bode’s Nebula
Type: Spiral galaxy
RA: 09h 55m 31s
Dec: +69º 04’ 04”
Constellation: Ursa Major
Size (arcmin): 25×12
Magnitude: +6.9
Distance: 12 Mly
Image
Date: 2013-01-04
Location: itelescope.net. Nerpio, Spain (T18)
Size (arcmin):37×27
Telescope: 12” f/7.9
Camera: FLI ML6303 (3072x2048pix)
Guiding: yes
Total exposure: 72 min (L: 8x3min; RGB: 8x2min each)
Processing: CCDStack, Photoshop CC 2016 and PixInsight