A blog post with more images and information
NGC 281 is an H II region in the constellation of Cassiopeia. It includes the open cluster IC 1590 and several Bok globules (dark doo-dads at center of the Blue area). NGC 281 is also known as the Pac-Man Nebula for its resemblance to the video game character from early 80's.
NGC281 spans over 80 light years at its estimated distance of 9500 light years.Technical details:
Processing work flow:
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Levels, curves and color combine in PS CS3.
Optics, Meade LX200 GPS 12" @ f5
Guiding, SXV-AO, an active optics unit, and Lodestar guide camera 12Hz
Image Scale, ~0,8 arc-seconds/pixel
24 x 1200s exposures for the H-alpha, emission of ionized Hydrogen = 8h
Optics and exposures used for colors
Tokina AT-X 300mm at f2.8
QHY8, a cooled single shot color camera
Baader UHC-s filter
Baader IR-cut filter
16x900s = 4h
Color channels for a mapped-palette image, O-III and S-II, are from an older image of mine.