The eastern veil nebula, NGC 6992, is part of a supernova complex known as the Cygnus Loop. The entire loop is quite large covering more than six degrees of sky so it’s much too large for most telescope/camera combinations to fit in a single frame. This is the eastern part of the loop, more commonly known as the eastern veil.
I imaged the western veil last year but was not really happy with my results. I was hoping to get a better result this time around given what I’ve learned in the last year.
I used 20 second exposures as the acquisition software recommended that though that would mean I ended up with more than 1,700 total exposures. I used Astro Pixel Processor to do the integration since it would largely run unattended and it’s a good thing it did because just the integration step took 29 hours. PixInsight would have been faster but also would have required more manual intervention. APP did a good job on the integration though so it was worth the wait.
I used APP’s “reduce light pollution” tool and it did a great job on the gradients. Once that was done I moved over the PI and finished processing there with the following steps:
- Channel Combination
- Photometric Color Calibration
- TGV Denoise
- Masked Stretch
- Star Reduction Script
- Adv Sharpening Script
- Curves Transformation
The sharpening script caused some ringing on the brightest white stars and I toned that down as best I could in photoshop.
One of my goals was to keep the background from getting that “fuzzy sweater” look that my images with dense star fields tend toward. I think that succeeded here and I was pleased with the amount of detail in the nebula. Overall I was trying to do as little to the data as I could but the massive number of stars had to be toned down or they overwhelm the nebula.
You can find the image at astrobin.