M101, NGC 5473-4, NGC 5477, NGC 5485-6; Ursa Major 
Astro-Physics 160 (160TCC) f/5.8 refractor 
Total Exposure Time: 17.6+ hours LHaRGB 370:300:130:120:140 minutes unbinned 
February 2010; NMS, Mayhill, NM 
Comments: M101 is readily seen even in small aperture telescopes as a slightly oval grey fuzzy blob. It requires larger apertures to tease out its spiral structure.  
This image was taken and processed with the intent of showing the much fainter outer arm of M101; these are not commonly seen. These arms can just barely be seen in an older version of M101 that I took with much less exposure time. Here is an inverted image of that luminance data stretched showing the faint arms.