Messier 101 (the Pinwheel Galaxy) in Ursa Major
Messier 101 (NGC 5457) is a face on spiral galaxy 21.8 million light years distant in the constellation of Ursa Major. It is 184,000 light years in diameter with an apparent size of 28.8' x 26.9'.
The galaxy was discovered by Pierre Méchain on 27 March 1781, who described it a "Nebula without star, very obscure and pretty large, 6' to 7' in diameter".
[Information from: Atlas of the Messier Objects; Stoyan et al; Cambridge University Press 2008 (English edition)]
M101 was photographed between 13 February and 12 March 2019 from an imaging rig in Spain that is privately-owned and remotely-operated by Barry Wilson and me.
Capture details are as follows:
Camera: QSI 690
Mount: 10 Micron GM2000HPS
Ha: 20 x 1200s
Lum: 65 x 600s
Red: 30 x 600s
Green: 30 x 600s
Blue: 30 x 600s
A total of 32 hours and 30 minutes exposure.
Data capture: Steve Milne & Barry Wilson
Image Processing: Steve Milne
Messier 101M 101M101NGC 5457NGC5457Pinwheel GalaxygalaxyMessier objectconstellationUrsa MajorPinwheel