M101 in Ursa Major

Posted by CraigAndTammy
on Tuesday, April 28, 2009
by Craig and Tammy Temple 
Even though it has a magnitude of 8.5, M101 is a difficult target due to it's low surface brightness. At 170,000 ly across, The Pinwheel is a large face-on spiral galaxy in the constellation Ursa Major covering almost 1/2 degree of the sky. Pierre Mechain discovered this galaxy in 1781, and Charles Messier verified its position. He then added it to his catalog as one of his final entries. This image was taken over 3 nights: April 23, 25 & 26, 2009. It is a total of 5 hours and 48 minutes integration time and the temperatures were 73° F, 76° F & 77° F, respectively.

  • Celestron C8 SCT with Celestron f/6.3 FR/FF
  • Atlas EQ-G w/EQMOD, Guided
  • Canon 350D (self-modified) w/Astronomik EOS Clip IR filter + 2" Hutech IDAS LPS filter
  • Best 67/90 180s & best 59/62 150s @ ISO 1600
  • Captured/Calibrated/Registered/Stacked/Initial processing in IP 3.75
  • Post processed in Photoshop CS4/Gradient XTerminator/Noise Ninja.
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