M101

From South Dublin Astronomical Society

M101
Type	Spiral galaxy
NGC	NGC 5457
Constellation	Ursa Major
Right Ascension	14h 03.2m
Declination	+54° 21'
Magnitude	7.7
Size	27 x 26 arc min.
Image:M101 messier image.jpg

M 101 is a beautiful face-on spiral galaxy that shows arms heavily dusted with star forming regions in detailed long exposure photographs. The binocular user though has to be content with admiring the combined light of its billions of stars as a pale grey smudge. The galaxy is quite easy to find as it lies to the other side of Eta Ursae Majoris, the last star in the handle of the Plough, to the better known M51. Sweep 5 northeast of Eta and you should spot the tenuous glow of the galaxy as a large roundish patch. Because we are seeing M101 face-on the surface brightness is quite low so you may scan over it at first. M 101 lies 27 million light years away and measures 170,000 light years across. It is the brightest of a small clutch of galaxies in this region of space that form their own local group.