The Bubble Nebula in Hydrogen Alpha (NGC 7635)
Characteristics:
Magnitude: about 7.0
Size: about 15'
Distance: 11,000 light years
Position Angle: minus 87 degrees (Pinpoint)
RA (J2000): 23h 20m 41s
Dec (J2000): 61 degrees 10' 50"
Description:
The Bubble Nebula is one of only a
few "bubbles" identified in the night sky. It is
an unusual nebula named for the surrounding bubble that is
seen in the upper right portion of the photograph above, caused by gas
ejected from a massive central star. The rate of ejected gas is
so brisk that it "runs into" the wall of the surrounding nebula, thus
creating a boundary of higher density gas that forms the outer shell of
the bubble. More information about this process may be found here.
Photographic
Details:
Date: August 21, 2008
Scope: Vixen VC200L at f9 (FL = 1800 mm) on the
Takahashi NJP
Mount
Autoguider: SBIG ST-402 with
60mm guidescope, focal length 227mm
Camera: Apogee U32 -20C
Filters: Astronomik
6nm Ha filter
Exposures: 13 x 20'
(unbinned); Total
exposure, 4.3 hours
Conditions: Transparency good; FWHM approximately 2.4"
Post-processing:
Debloomed, calibrated, aligned, and Sigma
Clip combined
in Maxim. DDP
in ImagesPlus (IP). Deconvolution in Maxim using Bob
Vanderbei's Fat Tail Deconvolution script (3 iterations).
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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