NGC281 - The "Pacman" Nebula

Object Description (Thanks to SEDS, the Chandra X-Ray Observatory, and Rob Gendler, for factual content):
NGC 281 (Sharpless 184) is a bustling cradle of star formation about 10,000 light years away.  The nickname for NGC281 is the "Pacman Nebula", and is derived from its resemblance to the famous early video game character.  I actually see this as a "devilish Pacman", due to the faint "horns" visible in the image.

The visible part of the nebula we see in this image is located about 2 degrees east of Alpha Cassiopeia, and is thought to be about 60 light years in size.  The central stars are being formed from the surrounding gas, which emits a large amount of hydrogen alpha (Ha) light after being excited by stellar radiation.

In this image, we see a small open cluster of stars, large lanes of obscuring gas and dust, and dense knots where stars may still be forming.  The dark areas overlaying the brighter ones in the middle of the image are dense clouds of gas known as Bok Globules.  The largest Bok globule seen in the image above is thought to be about 2.6 light years in diameter.

The cluster of stars near the large Bok Globule is an open cluster categorized as IC1590.  Made up of bright B and O stars, they provide the energy for excitement of the nebular material in the region.

X-ray data of this region shows gas of a temperature of a few million degrees and spectra illustrating significant amounts of magnesium, sulfur and silicon. The presence of these elements suggests that supernova recently went off in that area.

Dates Taken:
- 11/23 through 11/27, 2007

Equipment Used:
- TMB 203 F/7
- SBIG STL-6303
- Paramount ME
- Optec 3" rotator
- Starlight Instrument's Digital Feather Touch Focuser, (with electronic focusing)
- Astrodon narrowband 6nm Ha filter

Exposures:
- 15x30 minute subs, a total of 7.5 hours exposure

Processing:
CCDStack:
1)  Calibration with darks, flats, and bias frames
2)  Bloom rejection
3)  Impute (minor) bloomed pixels
4)  Image registration
5)  Normalization (Auto)
6)  Data rejection (Poisson sigma)
7)  Mean combine
8) Deconvolution, Positive Constraint, 25 iterations

Photoshop CS2:
1) Noel Carboni’s Photoshop action for “local contrast enhancement”
2) Shadow-highlight to bring up the background data
3) High Pass filtering technique to bring out large and medium-scale structures
4) Noise removal (NeatImage)
5) Contrast curve adjustment layer
6) Additional deconvolution and sharpening