30x240sec at iso 1600
30 Darks/Flats/Bias
C8 at 1260mm
Astronomik CLS filter


M101 in Ursa Major

Distance from earth 24 million light years


M101 taken with Astronomik CLS filter. This image was processed to the best of my ability for over 3 hours. Careful stretching, adding in blurred luminosity masks, and all the tricks I could come up with yielded this mediocre image. It is a lesson hard learned that imaging galaxies with light pollution filters is not a good idea. Galaxies are mixed spectrum light, like light pollution, and therefore the signal (galaxy) is filtered at almost the rate of the light pollution - unlike emission nebulas. Better to omit the filter and trust your stacking to increase the signal/noise ratio.

5-12-2007