The Crescent Nebula, NGC 6888 (a.k.a. Caldwell 27, Sharpless 105) is an emission nebula and was formed by the fast stellar wind from the Wolf-Rayet star WR 136. This wind collided with, and energized a slower wind previously ejected when the star became a red giant 400,000 years ago. Results of this are a shell and two shock waves, with one moving outward and the other moving inward. The inboard shock wave heats the stellar wind to X-ray-emitting temperatures. The nebula is located about 5000 light years away in the constellation Cygnus. (Source Wikipedia).

CAPTURE Information:

The image was captured with the iOptron CEM120 mount , the venerable Meade 12"LX200 SCT, and my Atik 383L+ m CCD at F7.16 (2182mm FL). Image subs were taken through Astronomik's narrowband filter OIII. Subs were done at 1x1 bin, -10C, at 10 minutes each.

IMAGE information -- 2019:

OIII : 32 subs (5.33 hr) on Sep 29th, Oct 9th and 11th.

Red: 20 subs (3.33 hr) on Sep 29th, Oct 2nd, 4th, 5th and 7th.

Green: 19 subs (3.17 hr) on Oct 1st, 2nd and 7th.

Blue: 20 subs (3.33 hr) on Sep 29th and Oct 4th.

Processing was done with PixInsight, following (for the most part) kayronjm's tutorial of Feb. 24th, several years back.

North is to the right (I think), and this is a slight crop due to the misalignment accumulation from so many different filters and times.

COMMENTS:

I've run at this target several times, always with the 12" Meade scope but likely with my original LX200 fork mount in 2012, and then the fork mount again in 2017 and now the iOptron CEM120. Looks like with my brief ownership of the Celestron CGE Pro, I was unable to get around to this target.

Anyway, no matter how I cut it, I cannot get a satisfactory Narrow Band combo of Ha, O3 and S2, even though I tried.

Also the displayed image is only the O3 combined with RGB. The Ha just did not do much with RGB.

While the finished product is a bit "dusty" looking, it does illustrate to my liking the almost transparent O3 nebula surrounding the RGB nebula.