Abell 21, The Medusa Nebula (Jim Raskett)

Abell 21, The Medusa Nebula

From Wikipedia:
The Medusa Nebula is a planetary nebula in the constellation of Gemini. It is also known as Abell 21 and Sharpless 2-274. It was originally discovered in 1955 by University of California, Los Angeles astronomer George O. Abell, who classified it as an old planetary nebula. Until the early 1970s, the nebula was thought to be a supernova remnant. With the computation of expansion velocities and the thermal character of the radio emission, Soviet astronomers in 1971 concluded that it was most likely a planetary nebula. As the nebula is so large, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported.The central star of the planetary nebula is an PG 1159 star.

Don’t find many deep-space targets that were discovered my birth year!I
I spent a few hours imaging this target a few weeks or so while testing some modifications to my HEQ5 mount (DEC axis tune-up). I had never seen or heard of this target before, but I needed a target in this part of the sky for testing. After a week of poor weather, I tried processing the 2:56 that I had and didn’t expect too much since the nebula is extremely dim and my skies are quite messy (especially near the Celestial Equator). I liked what I saw and anxiously waited for another opportunity to catch more data.

I finally got a break and collected another three hours (goes into the trees just after the meridian). Nowhere near enough data for this cool-looking dim target, but no clear nights ahead before the moon creeps back in, so I settled for 6.9 hours of total integration. Nowhere near enough exposure time and next year hopefully I can add more. Looking at the image after 2:56 vs. 6:56 integration, I saw a nice improvement in the definition of the serpentine filaments of glowing gas in the nebula “snakes”. Also, the wispy Ha below the
“snakes” is somewhat more visible.
Thanks you for looking and comments very welcome!
Jim

Original
B
C
Final
D

B

Description: More teal/green

Uploaded: ...

C

Description: Slight color adjustment.

Uploaded: ...

D

Description: Removed background green.

Uploaded: ...

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Status	Advanced success
Started	...
Astrometry.net job	9406224
PixInsight job	UKV96SWB3NF6W3JWDE8XXVOXW0GBCNAK
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	07h29m03s.35
RA (top/left)	07h31m20s.19
RA (top/right)	07h31m21s.94
RA (bottom/right)	07h26m45s.88
RA (bottom/left)	07h26m45s.64

Dec (center)	+13°15′12″.9
Dec (top/left)	+12°41′28″.5
Dec (top/right)	+13°48′35″.9
Dec (bottom/right)	+13°48′51″.9
Dec (bottom/left)	+12°41′43″.7

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