Friday, February 23rd, 2018

Pacman Nebula


NGC 281

This deep space object is officially classified as NGC 281, but many know it better as the Pacman Nebula. It is rich in Hydrogen emissions, and this shot represents an exposure of a little over 2 hours through a narrow-band filter passing only the Hydrogen emissions. It makes a nice black-and-white photo, I think. Color photos are in the works. From Wikipedia we learn this about the 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 beta1, 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.

Since it is getting cold out there in my backyard observatory, I have been doing my imaging using iTelescope’s T11 instrument situated in a New Mexico mountain valley at 7,300 feet.

T11 is a DEEP field telescope and its mission can be both an excellent imaging platform or do powerful science with photometrics. T11 is a major photon hunting science machine on the iTelescope network. This instrument can deliver pin-sharp images during 300-600 second unguided exposures, reaching magnitudes as low as 21.5 without too much effort.

For this image, I collected 14 10-minute exposures and integrated them into a single image, which was further tweaked using the PixInsight processing program. Remotely controlled from my computer, this telescope is a rather expensive but warm solution for my wintertime astrophotography. It’s specs are:

Optical Design: Corrected Dall-Kirkham Astrograph
Aperture: 510mm (20″)
Focal Length: 2280mm (0.66 Focal Reducer Fitted)
F/Ratio: f/4.5



2 Responses to “Pacman Nebula”
  1. Larry Ayers says:

    Nice image! There are some great details visible in the large version.

  2. Dave Ayers says:

    Thanks, Larry. The LHaRGB version is shaping up nicely as well. I hope to post it before the end of the year.

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