NGC 7331 and Stephan's Quintet from Bortle 8 Skies (Bogdan Borz)

NGC 7331 and Stephan's Quintet from Bortle 8 Skies

This image presents the Deer Lick group which is actually the galaxy group on the right upper part of the image, containing NGC 7331 the bigger galaxy and the smaller ones around it (called the "fleas" as I found out from Wikipedia). They are not interacting gravitationally, so it is not a galaxy group in a proper sense.

On the lower left part, we have Stephan's Quintet, a visual grouping of five galaxies of which four form the first compact galaxy group ever discovered. The group, visible in the constellation Pegasus, was discovered by Édouard Stephan in 1877 at the Marseille Observatory. The group is the most studied of all the compact galaxy groups. The brightest member of the visual grouping (and the only non-member of the true group) is NGC 7320, which has extensive H II regions, identified as red blobs, where active star formation is occurring. Four of the five galaxies in Stephan's Quintet form a physical association, a true galaxy group, Hickson Compact Group 92, and will likely merge with each other. (Wikipedia) Of course we all saw this Quintet as one of the first corners of our Universe imaged by the James Webb telescope.

Imaging this from my backyard in the city was a true challenge. I had to deal with the usual reflections on my raw files given the ambient light pollution. And of course, the signal to noise ratio is pretty low on the individual subs. But I was surprised to see a hint of IFN, especially around the Quintet, of course nothing similar to what can be obtained in a remote observatory under dark skies. The processing was almost completely done in Pixinsight.

Exposure :
September 21, 22, 23, 25; October 01 2022
L 22x300s 192 x 180 s
R 44x180
G 68x 180s
B 45x180s
Total exposure :19.3 hours

Light Polluted skies
Broadband under Bortle 7/8/9
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Status	Advanced success
Started	...
Astrometry.net job	6421264
PixInsight job	I4G82KW5POZZTL472CNKK8DHTEFKHVR4
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	22h36m39s.227
RA (top/left)	22h37m40s.269
RA (top/right)	22h38m10s.700
RA (bottom/right)	22h35m37s.698
RA (bottom/left)	22h35m09s.231

Dec (center)	+34°13′21″.49
Dec (top/left)	+33°47′56″.94
Dec (top/right)	+34°34′42″.23
Dec (bottom/right)	+34°38′44″.17
Dec (bottom/left)	+33°51′58″.91

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