So, I and Bostronomy are at it again with another collaboration, this time with a much harder target and a much wider field of view. The Cygnus Loop, aka Sharpless 193, is a large supermova remnant in the constellation Cygnus. It consists of deep space objects NGC 6960, NGC 6979, NGC 6974, NGC 6992, NGC 6995, and IC 1340. Common names for these areas are the Eastern and Western Veil Nebulae. This target is challenging for many reasons, but the shear amount of stars in this location as well as the deep sky gradient make it a very challenging are to not only image but to process as well.
We took our images in July, July and August and I went through many attempts to stack and process these images to get it to where we both were happy with the final result. The struggle with this was real – from having heavy distortion with the initial stacking to having terrible color gradients, though a lot of trial and error we finally ended up with this. A total of around 17 hours of data produces a pretty sweet image!
Equipment & Stats –
122 x 300s 800 ISO Radian Raptor 61 Canon EOS Ra Optolong L-eNhanced filter
76 x 300s RedCat 51 ZWO asi2600mc Optolong L-eNhanced filter
Calibrated and stacked in Astro Pixel Processor, processed in Siril and Photoshop.
The Cygnus Loop is a large supernova remnant within the constellation Cygnus which is now visible in the night sky in the Northern Hemisphere. The entire structure is around 3 degrees in size and sits around 2,400 light years away. It has an age of around 21,000 years. This target, for me, was one of the more frustrating targets. Its unique coloring, its “whispiness” and the sheer amount of stars make it a challenging target to both shoot and more importantly, process cleanly. In total, for the Western Veil images, I got around 5 hours of data total and I feel like to get it completely “clean” I would need around 15 more total hours for a total of 20 hours on target. I am hoping to get this amount in a more wide field, which I have already begun and is shown in the images at the end of this post.
These images where processed as an HOO image. This means three channels, one in Ha, and two in Oiii. This was down with a one shot color camera utilizing a dual narrowband filter – the Optolong L-eNhanced. The channels were separated in Astro Pixel Processor then recombined and then processed in Photoshop. I really like how the stars here have decent color, which is typically difficult to achieve when processing normally when using a narrowband filter.
These images have a more “traditional” processing method – stacking in Deep Sky Stacker then processing in Photoshop.
As you can see in both sets, there are a large amount of stars, even with star reduction techniques being used. The inverted images really show the star field and the deep contrast of the nebulosity.
Image & Equipment Information:
Meade Series 6000 80mm Triplet APO Refractor Canon EOS Ra Optolong L-eNhanced Filter Ho-Tech Field Flattener ZWO 30mm f4 MiniScope (guide) ZWO asi120mm (guide) Pegasus Powerbox Advanced
15 x 360s (6/16/2021) 30 x 420s (6/17/2021) Dark, flat, bias and dark flat frames for calibration ISO 800 – Taken in Providence, RI – Bortle 8
These images show the entirety of the Cygnus Loop. The annotated version is provided by astrobin.com. These were taken with a similar setup as the Western Veil images, but with the Radian Raptor 61 instead of the Meade 80mm. Here you can see the Western Veil at the top of the image with the Eastern Veil nebula at the bottom. Though I was planning on putting a lot of focus on the North American Nebula, I think I am going to put some time in on Eastern Veil with the Meade and the Loop as a whole with the Raptor. This image needs a lot more data as I only have just over an hour and a half so far.
Image & Equipment Information:
Radian Raptor 61 Canon EOS Ra Optolong L-eNhanced Filter ZWO 30mm f4 MiniScope (guide) ZWO asi224mc (guide) Pegasus Powerbox Advanced
20 x 300s (6/13/2021) Dark, flat, bias and dark flat frames for calibration ISO 800 – Taken in Providence, RI – Bortle 8
SNC Astro - Photo 