NGC 281, IC 11 or Sh2-184 is a bright emission nebula and part of an HII region in the northern constellation of Cassiopeia and is part of the Milky Way's Perseus Spiral Arm. This 20×30 arcmin nebulosity is also associated with open cluster IC 1590, several Bok globules and the multiple star, B 1.

It collectively forms Sh2-184, spanning over a larger area of 40 arcmin. A recent measurement estimated it lies 9200 light years from us. 

Colloquially, NGC 281 is also known as the PACMAN Nebula for its resemblance to the video game character.

Edward Emerson Barnard discovered the nebula in August 1883, describing it as "a large faint nebula, very diffuse." Multiple star 'B 1' or β 1 was later discovered by S. W. Burnham, whose bright component is identified as the highly luminous O6 spectral class star, HD 5005. It consists of an 8th-magnitude primary with four companions at distances between 1.4 and 15.7 arcsec. There has been no appreciable change in this quintuple system since the first measures were made in 1875.

The nebula region 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:

"There was a faint glow in the immediate vicinity of the multiple star, with an occasional impression of a much larger nebulosity...Its surface brightness was much less than that of M33 in Triangulum or NGC 205, the distant companion of the Andromeda galaxy."

[Source: Wikipedia]

CAPTURE Information:

The image was captured with the iOptron CEM120 mount , the venerable Meade 12"LX200 SCT, and my Atik 383L+ mono CCD at F7.16 (2182mm FL).

Image subs were taken through Astronomik's narrowband filters Ha, SII and OIII.

IMAGE information -- 2020

Ha : 72 subs (12.0 hr) on Aug 28th, Sep 11th, 18th and 19th.

OIII : 72 subs (12.0 hr) on Sep 11th, 18th and 19th.

SII : 72 subs (12.0 hr) on Aug 30h, Sep 7th, 11th, 18th and 19th.

All exposures were at 10 minutes (600s) each, 1x1 bin and -10C.

Processing was done with PixInsight, following (for the most part) kayronjm's tutorial of Feb. 24th from several years back.

The two panels each of Ha, SII and OIII were individually integrated, then merged, and lastly combined. The three assemblies then created the Hubble Palette, using PixelMath and the following “SHO” formula:

Red = SII

Grn = Ha

Blu = OIII

Luminance was created using only subs from the Ha filter.

In this case I have no idea where North is.

This for me was an unusual Mosaic effort. I don’t normally do mosaics because of the additional work and time that goes into one.

The above quantities for Ha, OIII ans SII represent 36 subs from each of the upper and lower panels.

COMMENTS:

I put a genuine effort into bringing out the gold and blue colors. And was fairly pleased with the results.