NGC 281, Pacman Nebula


NGC 281 is an H II region in the constellation of Cassiopeia and part of the Perseus Spiral Arm. It includes the open cluster IC 1590, the multiple star HD 5005, and several Bok globules. Colloquially, NGC 281 is also known as the Pacman Nebula for its resemblance to the video game character.

The nebula was discovered in August 1883 by E. E. Barnard, who described it as “a large faint nebula, very diffuse.” The multiple star HD 5005, also called beta-1, was discovered by S. W. Burnham. It consists of an 8th-magnitude primary with four companions at distances between 1.4 and 15.7 seconds of arc. There has been no appreciable change in this quintuple system since the first measurements were made in 1875.

The nebula is visible in amateur telescopes from dark sky locations. In his book Deep Sky Wonders, Walter Scott Houston describes the appearance of the nebula in small telescopes.

Imaging telescopes or lenses: Astro-Physics AP 130mm f/6.3 Starfire EDF
Imaging cameras: SBIG STXL-11002/FW8G-STXL
Mounts: Astro-Physics Mach1AP GTO with GTOCP3
Guiding telescopes or lenses: Astro-Physics AP 130mm f/6.3 Starfire EDF
Guiding cameras: SBIG STXL-11002/FW8G-STXL
Software: Pixinsight 1.8, Photoshop CS5, Maxim DL Pro 5
Filters: Astrodon 3nm SII, Astrodon 3nm OIII, Astrodon H-alpha 3 nm
Resolution: 2719×3600
Dates: Dec. 4, 2014, Dec. 6, 2014, Dec. 11, 2014
Astrodon 3nm OIII: 13×900″ bin 1×1
Astrodon 3nm SII: 14×900″ bin 2×2
Astrodon H-alpha 3 nm: 26×900″ bin 1×1
Integration: 13.2 hours
Avg. Moon age: 15.16 days
Avg. Moon phase: 91.20%
Locations: My back deck, Glen Ellyn, IL, United States