Layered processing of NGC7000

Here is a recent processing effort on some data collected last year. The North American Nebula has always been a difficult target as I use an unmodified Canon DSLR which doesn't have the best H alpha sensitivity. In order to make the nebula visible, extreme stretches are generally needed. These stretches usually result in bloated and excessive numbers of stars then tend to obscure the nebula. By splitting the stars and nebula out to separate layers the nebula can be stretched without over doing the stars. Noise reduction can be applied without overly blurring the stars allowing a much more balanced image. The image below is the result of split star processing and a statistical noise filter applied several times throughout the processing. Click on the image to see an earlier version with more conventional processing. Click again to return to the original image.
Object NGC7000 RA 21:01.08 Dec 44:12
Exposure 30 minutes (6 X 5 minutes)
ISO 1600
Camera Canon 350D DSLR
Optics 70-300mm Sigma lens set to 190mm at f5.6
Location St. Croix Observatory
Processing  Statistical noise reduction applied then the image was stretched using the arcsinH function in Images Plus. Stars were split out from the image and the nebula colour was enhanced using the additive colour balance function with a blurred luminance mask. Curves with a screen blend mode and a luminance mask was used to increase the contrast and brightness of the nebula image. The star layer was recombined with the processed nebula layer and a levels adjustment used to set the final contrast.