NGC 281 (Pacman Nebula)
Characteristics:
Magnitude: 7.0 (open star cluster)
Size: about 35'
Distance: ?10,000 light years
RA: 0h 52m 48s
Dec: 56 degrees 37' 0"
Description:
NGC 281 is a star cluster associated
with nebulosity. The young, blue central stars are being formed
from the surrounding gas, which emits in Ha as it is excited by stellar
radiation. The nebulosity of this region is faint and can be best
appreciated in long exposure images such as this. The nickname
"Pacman Nebula" derives from its appearence when viewed sideways
(although I prefer the above orientation).
Photographic
Details:
Date: August 7, 2005
Scope: Takahashi
FS102 at f8, on the G11 Losmandy
Mount.
Autoguider: SBIG STV with
e-finder.
Camera: Maxcam CM10.
Filter: Astrodon
Ha filter (6 nm bandpass); Astronomik RGB type II filter set; IDAS LPS
filter used for this image to suppress light pollution near the
northeast horizon.
Exposures: Ha filter, 8 x 10'
each unbinned.
RGB, 25 minutes each (5 x 5'), binned 2x2. Total exposure: 155
minutes.
Conditions: Temperature 75 degrees F; above average
transparency, below average seeing; calm; intermittent clouds. I
shot the RGB frames at the beginning of the session during relatively
clear skies, but the Ha portion of imaging was limited to only 80
minutes due to clouds.
Post-processing:
This represents an Ha:HaR:G:B image.
Subs were debloomed with Ron Wodaski's
Debloomer software, dark frame calibrated, and then
aligned in Registar. Sigma combined using RC Sigma Reject
MaximDL, followed by DDP
in ImagesPlus (IP). Further processing in Photoshop CS (16
bit format).
Please
note: Graphics on this website
may not be reproduced without author permission.
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