Skies By Africa

Images of the Heavens By Eric Africa

NGC 281, the PacMan Nebula

NGC 281
Hubble Mono H-alpha
NGC 281 is another beautiful emission nebula in Cassiopeia. It is nicknamed the PacMan Nebula for its resemblance to the video game hero of the 1980's. Compared with other emission nebulae, NGC 281 is relatively small, about 35 arc-minutes across (slight larger than the Full Moon).

The "Hubble Palette" image (the left thumbnail version) was narrowband color mapped similar to popular images from the Hubble space telescope: SII data mapped to Red, H-alpha data to Green, and OIII to Blue. The stars were given a natural color from the RGB data. The HaRGB version uses the H-alpha data as luminance and RGB data for color.

Like many emission nebula, NGC 281 is a busy star-forming region. Open cluster IC 1590 is associated with the nebula and is composed of stars born within it. The dark region forming the nebula's "mouth" is actually a foreground dark nebula blocking light from the nebula and stars behind it. While the nebula is relatively bright, I have not seen it visually yet, not that I've tried.

Humor: Ever wondered what the PacMan is running from? I think I found it.
Constellation: Cassiopeia
When Visible: October - March
Distance: 9,500 Light-years
Date: October 2011
Location: Rancho Hidalgo, Animas, NM
Exposure Details:
H-alpha: 22 x 30 minutes Binned 1x1
SII: 25 x 30 minutes Binned 1x1
OIII:  21 x 30 minutes Binned 1x1
R: 6x 10 minutes Binned 1x1
G: 6x 10 minutes Binned 1x1
B: 6x 10 minutes Binned 1x1

37 Hours total exposure time for the Hubble/RGB palette! 14 Hours for the HaRGB version.
Equipment Used:  Takahashi TOA-130F on an Astro-Physics AP1200GTO mount. SBIG STL-6303E camera with FW8-STL filter wheel and Astrodon LRGB and narrowband filters. Robofocus focuser and Astrodon Takometer rotator.
Acquisition Software : MaximDL 5, TheSky6, CCDAutopilot 4, FocusMax, Takometer Controller
Processing Software: MaximDL, Photoshop CS, Carboni Actions, Croman GradientXterminator, IrFanView
A version of the 2004 data with RGB data added can be seen here. 18 x 15 Minutes H-alpha Binned 1x1. RGB: 12x5 minutes through each filter, binned 2x2. Borg 76ED on a Takahashi Temma-2 mount. SBIG ST-8XE with 5-position filter wheel and Custom-Scientific filters. 2004 H-alpha only data from 2004 can be seen here. 2006 H-alpha data can be seen here. FSQ-106 and 6303, 6x30 minutes H-alpha.