M101

Ursa Major - Spiral Galaxy - Magnitude 7.9

M101 - Spiral Galaxy in Ursa Major

M101 forms a perfect equilateral triangle with the last two bright stars in the handle of the big dipper. This makes this spiral galaxy easy to find, but not necessarily easy to see. Though the picture doesn't show it, M101 is actually very large in apparent size, nearly 30 square arc mintues. Therefore, the magnitude of this object is spread over a large surface area. For this reason, dark skies and bigger apertures are necessary to bring out the spiral structure, though the entire galaxy is also visible in a good small scope, even in binoculars. One more interesting thing about this object: this is a duplicate object in the Messier catalogue. Not only is it the 101st object, but also the 102nd. This is why we say there are only 109 Messier objects, even though the last one is numbered M110.

Location: Ballauer Observatory in Azle, Texas
Seeing: 8/10 (1.4 FWHM)
Transparency: 4/10
Date and Time: December 29, 2003 @ 11:00PM
Equipment: Tak FSQ-106 @ f/5, and Celestron CGE mount
Camera: SBIG ST-7E with CFW-8a color filter wheel, standard SBIG filters
Exposure Info: LRGB image (L = 5 x 10 minutes, R = 3 x 5 minutes, G = 3 x 5 minutes, B = 5 x 5 minutes) all binned 1x1
Processing Information: Dark frames, gradient removal, registration, Sigma combine and DDP in MaxIm 3.0. Levels, Curves, Gaussian Blur and Unsharp Mask in Photoshop 7.

Exposure Notes: Composite images were taken low in the sky in too much light pollution. Although this shot has 105 minutes of total exposure time, the size of the galaxy should fill the frame from top to bottom. Need much more exposure time in like conditions.