NGC 281, commonly known as the Pac-Man Nebula for its resemblance to the video game icon, is a HII region located in the constellation of Cassiopeia at a distance of approximately 9,600 light years. The visible structure of the nebula spans a distance of approximately 60 light years. Like in the Eagle Nebula, the Pacman contains several pillars and dark globules. These areas are active stellar nurseries where new stars are being created. Dr. Robert Gendler published an very informative article describing, in some detail, the Pac-Man Nebula. It may be viewed here.
The image above was compiled from narrow band filtered exposures to create a mapped color depiction of the Nebula. A Bi-Color palette with Ha mapped to the red channel and OIII mapped to the greem and blue channels was utilized. This mapping technique results in a Near True Color Image.
A full narrowband (SII/Ha/OIII0 Hubble Palette version the NGC 281 may be viewed here.
1http://en.wikipedia.org/wiki/NGC_281