SH2-136 - Ghost Nebula

SH2-136, nicknamed The Ghost Nebula (a.k.a. VdB 141), is a faint reflection nebula in the constellation of Cepheus. The Nebula sits in a heavily dusty region known as the Cepheus Flare molecular cloud complex and is approximately 1,400 light-years away and two light-years across. Star formation is occurring in dense areas of the nebula in fact the bright area with a V-shaped projection on the right end of the nebula is a protostar forming. The projection is believed to be caused by outflow of the rotating accretion disk.

This has been on my someday list but I waited until I had a scope capable of getting some finer detail including some the protrusions pointing upwards which resemble fists with fingers pointed outwards - one of my favorite parts of the nebula. I purposely did not crop it because I wanted to show the even fainter dust which lies on the right side of the main nebula and of course the relatively bright portion on the top of the image. Most of the stars appear slightly yellow being obscured by the dust but some of the large bright blue ones still shine through. Also, I spent some extra star reduction on the larger stars which was a bit tedious but worth it.

This nebula is very faint and really was not in my subframe when imaging with 3-minute exposures. Three minutes is about the maximum I feel comfortable with without using any type of light pollution filter in my neck of the woods. I believe I have found the optimal back focus at 108.5mm for my system at last after several tweaks. I started with the recommended 105mm, then 106.5mm, then 109.5mm, and finally 108.5mm. If you have been following my PixInsight/ASI24MC escapades (https://www.youtube.com/watch?v=Ot5x63kya6A&t=3s), I managed to use PI without the artifacts this time. Could be that I have a better system but I'm not sure yet. I have to test it with the NBZ filter to be sure. Lastly, normally I orient objects so north is up but it looks more like a ghost with south being up.

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SH2-136 - Ghost Nebula (VdB 141)

Dates: 8-2, 8-5
Camera: ZWO ASI294MC-Pro
Telescope: Celestron EdgeHD 800
Barlow: None
Focal Length: 2032mm (native)
F/10 (native)
Focal Reducer: Celestron .7 Reducer Lens
Mount: Orion Atlas Pro
Filter Adaptor: ZWO Filter Drawer
Filter: Baader UV/IR Filter (2-inch)
Focuser: ZWO EAF
Autoguiding: ASI120 Mini attached to an Orion ST80
Exposure: UV/IR 124 x 180
Gain: 120
Offset 0
Temp: 0 C
Processing: Asiair app, PixInsight, Photoshop, Gradient Exterminator, Topaz DeNoiseAI.

https://www.instagram.com/astroquest1/
http://astroquest1.blogspot.com/
https://www.astrobin.com/users/kurtzepp/collections/
http://youtube.com/c/AstroQuest1