NGC6888

My first bi-colour narrowband image of the Cresent Nebula, the total integration time is 14.5hours. 

Ha is mapped to red, OIII is mapped to blue and synthetic narrowband green was created from a combination of Ha and OIII via Noel's actions. I also decided to show a few subs of broadband data in order to create a more realistic starfield and decided to try out creating synthetic broadband green. The Ha, OIII and synthetic green where blended using the PS technique described by Don Goldman in Lessons from the Masters. Having created an RGB image I then created a synthetic narrowband luminance image on which I performed all sharpening and contrast enhancement.  The star field was processed separately and blended into the narrowband image via a star mask.  

LIGHTS: L:5; B:12; x 600s; Ha:5; 16 x 1800s.; DARKS: 30; FLATS: 40; BIAS: 100 all at -20C.