M27 stretched red

M27 (Dumbbell Nebula). Processed using DSS. 

Hardware details: Camera: Nikon D200. Telescope: SW Evostar 120 with Baader UHC-S filter. Mount: AZ-EQ6 guided using a ST80 synguider. Image details: Lights: 39 x 3min at ISO 800, Darks: 20 x 3min 20sec at ISO 800 (from dark library), Lights and darks separated by 30 sec intervals. Flats: 40 x 1/40s at ISO 800, Bias: 30 x 1/8000 at ISO 100

Date of capture 30/04/2016 & 08/05/2016. Increasing cloud stopped imaging after about 1 hour, some wind, seeing was reasonable. The second night was less cloudy but transparency was much worse. Guiding was not great in RA but fine in DEC, PA was ok - I think I might have knocked the scope at some point in the night. The second night gave better auto guiding. 

I increased the saturation by 25% and manually aligned the colour channel histograms. I stretched the red colour histogram more that green or blue to increase its contrast. This helped bring out some of the nobbled structure within the nebula. 2x drizzling was done on DSS.