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| 5 x 120 second frames taken with my 400D Canon DSLR with telephoto lens at f = 80 mm. all on a driven NEQ6 mount. Frames stacked using DeepSkyStacker and finished with APS |
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| Image of M101 enlarged in APS and pasted into the original photo to show location |
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| M101 further enlarged to show the spiral nature of the galaxy |
Messier 101, also known as the Pinwheel Galaxy, is 21 million light years away in the constellation Ursa Major (The Great Bear). The combined light from this galaxy has an apparent magnitude of 7.86, so it cannot be seen with the naked eye. If you view M101 from a very dark site and know exactly where to look, it can be seen through tripod mounted or image stabilised binoculars. I find this a very difficult object even through my 11x80mm binoculars! A bit more magnification helps.
M101 is a face on spiral galaxy with abundant hydrogen gas clouds which are being gravitationally compressed to create new stars. The bright pink areas in my above image clearly show these areas of star birth. M101 is similar to our own Milky Way but 70% larger. The Pinwheel Galaxy has a mass of approximately 103 billion times that of our Sun but strangely has a comparatively small black hole, between 20 and 30 times the mass of our Sun, at its centre. The black hole at the centre of the Milky Way is estimated to be equivalent to 4,100,000 solar masses.
In August 2011 a Type 1a supernova was observed in M101. At its brightest the supernova reached magnitude 9.2. Sadly, I never got to see this supernova through the eyepiece, let alone image it.
Given the success I have achieved in imaging this galaxy with a telephoto lens, on the next clear night I will turn my big telescope towards this intriguing island universe 6 megaparsecs distant from our small but beautiful planet Earth.
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| M101 credit NASA-ESA |
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