NGC 6888 the magnificent Nebula (John Favalessa)

NGC 6888 the magnificent Nebula

Ha = 91x300 sec; Sii = 73x300 sec; Oiii = 119x300 sec all at 100 gain.

I've been fascinated by this emission nebula in the crowded Cygnus region, not far from my last post, especially the oxygen. I really don't know what I'm doing with narrowband yet, so I tried many different combinations and finally settled on foraxx palette which seems to enhance the oxygen the most. I know other images of this show much different nebula color, but it was the oxygen which fascinated me. I wonder how the heck did this happen? and what is that dark spot near the middle? so from wikipedia: "It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000] to 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures."

I used Pix deconvolution separately on the Ha, Sii and Oiii and used Ha as luminance masking out the nebula though. Slight star reduction and very mild noise settings in Topaz: noice reduction 6; sharpness 0; recover original detail 15; color noise 6.

I have good data even though from my backyard with waxing moon and will definitely reprocess again as I've noticed most images use Ha and Oiii only.

Original
Final
B

B

Description: A total reprocess but this time in HOO. The oxygen I was going after in the Original is even better now! (thanks Gary). essentially the same workflow, better masking and light Topaz noise reduction as the original.

I still was fascinated by "what the heck is going on" to create this nebula. From wikipedia but about the star in the middle that caused this: According to recent estimations, WR 136 is 600,000 times brighter than the Sun, 21 times more massive, and 5.1 times larger. Its surface temperature is around 70,000 kelvins. WR 136 blew off a shell of material when it became a red supergiant around 120,000–240,000 years ago with a mass of around 5 M and this is still expanding at 80 km/s. Currently, its fast stellar wind, ejected from the star at around 3.8 million mph (1,700 km/s), is catching up to the material ejected from the star and shaping it into a shell. Ultraviolet rays emitted from WR 136's hot surface cause the shell to glow.

There is some evidence WR 136 may be a binary star. Its companion would be a low-mass star of spectral classification K or M that would complete an orbit around the Wolf-Rayet star each 5.13 days, being the progenitor of a low-mass X-ray binary system

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Status	Advanced success
Started	...
Astrometry.net job	4800580
PixInsight job	AXQY63WO9YSWF9O8GTGM9TOKSROM3WAP
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	20h12m11s.11
RA (top/left)	20h09m19s.86
RA (top/right)	20h08m46s.50
RA (bottom/right)	20h14m57s.76
RA (bottom/left)	20h15m41s.14

Dec (center)	+38°19′50″.8
Dec (top/left)	+39°16′37″.4
Dec (top/right)	+37°27′58″.8
Dec (bottom/right)	+37°22′55″.5
Dec (bottom/left)	+39°11′24″.3

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