M101 (NGC5457) in Ursa Major is often called the pinwheel galaxy, as is M33 in Andromeda. In my opinion M101 looks more like a pinwheel than M33 does. Anyway, M101 is a large spiral galaxy, seen face-on. Face-on galaxies, have a low surface brightness, which makes them hard to detect visually. I have to admit that I never saw M101 directly, although I tried many times. The photograph proves that I was looking at the right position :-) Charles Messier discovered M101 March 27, 1781, and it's estimated distance is 17,5 million lightyears.

EXPOSURE DATA: TAL 150 PM 150mm f/5 Newtonian telescope on a Vixen SP equatorial mount; Starlight Xpress MX5-C CCD camera; 34 out of 40 unguided exposures of 60s; taken on April 2, 2005 from my backyard in The Hague, The image suffers a bit from noise, which probably indicates that I was a little low on exposure-time. An older webcam image is shown below.

Since the april 2005, I tried many times again to make a decent photograph of M101, but I haven't succeeded so far. The above picture shows the outcome of my March 22, and April 7 2007 attempts. During the first session the wind was blowing quite hard and it was very cold that night. I used a C5, operating at f/5 on my SP mount, and I took 70 frames of 60s each, with the mount guided by Starlight Xpress S.T.A.R. 2000.

S.T.A.R. 2000 causes some amp-glow, which was nearly as strong as the weak signal from this low surface-bightness galaxy. It also messes up the colour registration of the MX5-C so I took 25 unguided frames afterwards just for colour registration. Although not a total failure much remained to be desired. That's why I tried again on April 7. I used my 10" f/4 Newtonian this time to shoot 69 frames. Autoguiding was done with a Meade LPI through a 500m f/5.6 Rubinar (Maksutov) camera lens. It went quite alright, apart from image shift due to lexure of the mounting of the Rubinar, but later on I discovered that I missed my mark during focussing. The focusser somehow got stuck, rendering half of the picture unsharp. Combining the usable parts of it with the recording of March 22, finaly resulted in the picture above.