Crescent Nebula (NGC 6888) and "Soap Bubble" Nebula (PN
G75.5+1.7)
Position:
RA: 20h 13m 28s (J2000)
Dec: +38 degrees 15' 12" (J2000)
Description:
The
Crescent Nebula in the upper right portion of this image (NGC 6888) is
the result of a dying central Wolf-Rayet star (WR 136) that is shedding
massive amounts of gas and UV irradiation, the latter exciting hydrogen
and oxygen to emit in the red and blue wavelength ranges,
respectively. It's estimated that the central Wolf-Rayet star
responsible for forming the Crescent Nebula will go supernova within
the next 100,000 years. The "Soap Bubble" nebula (PN G75.5+1.7),
located in the lower left portion of the image, is a planetary nebula
recently
discovered by amateur astronomer Dave
Jurasevich on July 5, 2008. It is well worth reading Dave's
account of this discovery, which also shows some of the original
data that reveals how faint this object is. It took a lot of work
for me to dig this nebula out of the background, but it was well worth
the effort. More information on NGC 6888 may
be found on
Rob
Gendler's webpage.
Photographic
Details:
Dates: August 19, 20, 21, 2017
Scope: Takahashi
FSQ106 at f5 on the Takahashi NJP
Mount
Autoguider: SBIG ST-402 with
60mm guidescope, focal length 227mm
Camera: Starlight XPress SX814
CCD camera at -20C, resulting in an image scale of 1.44 arcsec/pixel
with the FSQ106
Filters: Baader Ha, OIII, RGB
Exposures: Total
exposure 16 hours
Post-processing:
Calibrated, aligned and
stacked in Maxim, 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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