Hemisphere:  Northern  ·  Constellation: Cygnus (Cyg)  ·  Contains:  IC 1340  ·  IC1340  ·  NGC 6992  ·  NGC 6995  ·  NGC6992  ·  NGC6995  ·  Veil nebula
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NGC 6992, Eastern Veil Nebula in OSC, 


            Alan Brunelle
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NGC 6992, Eastern Veil Nebula in OSC

Getting plate-solving status, please wait...
NGC 6992, Eastern Veil Nebula in OSC, 


            Alan Brunelle
Powered byPixInsight

NGC 6992, Eastern Veil Nebula in OSC

Imaging telescopes or lenses: Celestron RASA 11

Imaging cameras: ZWO ASI071MC PRO

Mounts: Celestron CGX-L

Guiding telescopes or lenses: Agena Astro Finder Scope

Guiding cameras: ZWO ASI 120 MM Mini

Software: IrfanView  ·  Pleiades Astrophoto PixInisight 1.8 Ripley (x64)  ·  Cartes du ciel  ·  Sequence Generator Pro  ·  PHD2  ·  Wolfgang Zima Mobile Observatory 3 Pro

Filters: Optolong L-Pro 2"

Accessory: Baader Planetarium RASA 11 UFC system with 2" filter slider

Dates:July 18, 2020

Frames: 42x240" (2h 48')

Integration: 2h 48'

Avg. Moon age: 27.26 days

Avg. Moon phase: 5.72%

Astrometry.net job: 4046181

RA center: 20h 56' 32"

DEC center: +31° 24' 1"

Pixel scale: 1.596 arcsec/pixel

Orientation: 13.223 degrees

Field radius: 1.308 degrees

Resolution: 4920x3263

Data source: Backyard


The Eastern Veil is thought to be the result of a shock wave moving through the progenitor star's remnant planetary ejecta. The progenitor having gone supernova well after much of the star's material was ejected. An example would be the massive clouds of gas and dust emitted by a Wolf-Rayet star in advance of the inevitable (?) explosion. The question mark is because I have recently read that some massive stars are so prolific in mass ejection that they can actually reduce their overall mass beyond that which would eventually allow for a supernova. This supernova occurred some thousands of years ago. Most of the emitted gas has expanded and cooled and is not visible, however the supernova shock wave is exciting that gas into these overlapping crepe-like emission veils. The Eastern Veil is part of the much larger Cygnus Loop complex. My guess is that this may have been much brighter some centuries in the past because of increased density and concentration and energy of the shock wave.

As old as this object is and delicate as this structure appears, it actually is bright enough for visual telescopy. I can barely make this out visually and also the Western Veil with my 5 inch Mak Newt. And it is even more easily distinguished when employing a UHC filter. But, of course, no colors!

Given that this is a visual target, you would think that my 240 sec exposures here seem rather extravagant for an 11 ich RASA. At 240 sec, the larger stars were getting close to saturation. and the dense starfield is something to deal with. I see that this object is a very popular subject, though, by far, most often in narrow band. Narrow band appears to have the advantage of gaining some of the very faint Ha structures outside of the main Veil body, and as with the use of a UHC filter for visible viewing, the narrow band filters no doubt beat down a lot of the star field. I am not sure I could get much more with longer subs or more subs. Unlike my last few projects posted here, this one was not shelved because I had too little data, but rather my experience with the Western Veil left me less than excited to complete this project. I have since learned some new processing techniques and thought that I would give it a go. I am happy enough to post this and motivated to get back and reprocess my Western Veil as well!

Finally, I note a decent number of galaxies can be seen in this field of view, especially on the side ahead of the leading edge of the shock wave (Left). Even a couple within the bright Veil. However, I could only find a few within the Cygnus Loop area and I wonder if this is because the dark dust and gas is more dense and opaque on that side? My processing has not been too kind to these small background objects however!