Crab nebula (M1) First attempt

Date of image 10/09/2016

The Crab nebula (M1). Processed using DSS. 

Hardware details: Camera: Canon 600D (astro modded). Telescope: SW Evostar 120 with Baader UHC-S filter. Mount: AZ-EQ6 guided using a ST80 synguider. Image details: Lights: 15 x 3min at ISO 800, Darks: 50 x 3min 0 sec at ISO 800 (from dark library), Lights and darks separated by 15 sec intervals. Flats: 100 x 1/1250s (taken from cloudy sky) at ISO 800, Bias: 50 x 1/4000 at ISO 100. 

The weather was ok - high level clouds throughout the whole night interrupted by thick lower level clouds at about 2:00am.

Processing was done in DSS, I increased the saturation by 30% and manually aligned the colours. I had a big problem with flats when processing this image. For some reason, the lights were 'flatter' (i.e. had more uniform illumination) than my flats. This lead to over-correction when applying my flats. I am not sure what happened to cause this change in my lights but the scope was pointing near my neighbours bright garden light, maybe scattered light caused this issue. 

The image is showing detail within the nebula - the nebula is smaller than I thought so I used 3x drizzle to reduce the pixel size. I need more exposures on this target, still lots of nose to fight (especially in the green channel). I stretched the colour channels about the same amount here.