M101 - Pinwheel Galaxy and friends (M101 Group)

The Pinwheel Galaxy (also known as Messier 101 or NGC 5457) is a face-on spiral galaxy about 27 million light-years away in the constellation Ursa Major.
It was discovered by Pierre Méchain on March 27, 1781, and he subsequently communicated his discovery to Charles Messier who verified its position and added it to the Messier Catalogue as one of the final entries.

M101 is a relatively large galaxy compared to the Milky Way. With a diameter of 170,000 light-years it is nearly twice the size of the Milky Way. It has a disk mass on the order of 100 billion solar masses, along with a small bulge of about 3 billion solar masses.

Telescope: Skywatcher ED80 & William Optics FF/FR 0.8 II
Mount: HEQ5 Pro
Camera: QHY8
Filter: IDAS LPS
Guidescope: Skywatcher 70/500mm
Guide with LVI SmartGuider
Exp. Time: 3 hours & 40 min (11*20 min subframes), bin 1x1
Calibration Frames: 50 flat, 50 bias, 10 darks
Capture: Nebulosity 2.2.5
Stack: Deep Sky Stacker
Processing: Photoshop CS3
Date: 4 April 2010
Location: Ancient Epidauros, GR

M101 - Pinwheel Galaxy Wiki