NGC 281 is an HII
region in the constellation of Cassiopeia. It includes the open
cluster IC 1590, the double star HD 5005, and several Bok globules.
NGC 281 is about 10,000 light-years away. Sometimes called the
Pacman nebula, because when viewed though a telescope it resembles
the video game character.
This false color image was acquired with Ha, SII and OIII filters
mapped to the RGB channels respectively. The colors of top image
more closely follow the Hubble Palette. The presence of sulfur,
hydrogen and oxygen are more clearly shown. Red indicates the
presence sulfur, green hydrogen and blue oxygen. With no color
manipulation, the image would be basically green, due to the
dominance of hydrogen.
The lower image was severely processed to produce ever popular
and blue colors, but still reveals a similar structure to the