NGC6992 The eastern Cygnus Loop. This image was taken under hazy sky conditions with bright moon light and light pollution to contend with, stars were only visible down to magnitude 3.5. I was using a set of Astronomik narrowband filters S11, O111 and HA combined with RGB filters . I was also using a 4 inch f/6.3 refractor, a Vixen Atlux mount, PHD auto-guiding and an Atik 383L mono CCD camera. I captured five minute sub-frames with matching dark-frames and combined them with flat-field frames to reduce the effect of vignetting in the final image. The total exposure times were 50 minutes using a HA filter, 40 minutes using an O111 filter, 30 minutes using a S11 filter, and 10 minutes using each RGB filter.
Bi-colour image
Hubble Palette
RGB + Hubble Palette
Narrowband luminance RGB colour
