Thor's Lightning (SNR G150.3+4.5), MarSai 1, Sh2-204, 207, 208, and 210 (Three-Panel Mosaic)

Image Title: Thor's Lightning (SNR G150.3+4.5), MarSai 1, Sh2-204, 207, 208, and 210 (Three-Panel Mosaic)

Copyright: Timothy Martin

Date image was taken: January 06, 2025

Location: Deep Sky West Remote Observatory near Santa Fe

Data Acquisition Method: Personal Telescope Setup

Image Description and Details: This little thing turned out to be a ton more work than I anticipated. Although I've spent a lot more effort capturing an image, this was a really hard one to put together in the end. I think, however, that it was worth the effort. While there are a few images of Thor's Lightning out there, I couldn't find any at all that showed the true extent of the supernova bubble, so maybe this is an image of first impression not only for Astrobin, but also in general.

As is fairly usual for me, I wanted to go after a lesser-imaged region and try to turn it into something unique and visually informative. I'm not sure I achieved that--it's up to the viewer to decide. I spent over a week trying to get the right blend of LRGB and HOO and I'm not sure I've done that either. But it's not for lack of trying. After attempting several methods in PixInsight to do the blending, I was never happy with it. I finally wound up using Photoshop to combine all the channels. That wound up taking several more days in fits and starts.

Another challenge was stitching the mosaic. I had noticed several weeks ago that my polar alignment was drifting. It became more and more apparent in capturing the first panel for this mosaic because I was seeing noticeable, but not terrible, field rotation over the course of a night. I hate to ask the observatory techs to engage in after-dark, open-roof activity in the dead of the New Mexico winter at 8,200ft above sea level. But I finally did ask Thomas to adjust my polar alignment. It turns out that I was off by a whopping 10'. Eek! So I shot the second two panels after polar alignment. When I first stitched the three panels together, there was plenty of overlap to get the job done, but the first panel was rotated by about 10 degrees. Ouch. I could have made it work, but I would have had to chop off about half of Sh2-204, which is one of the most important features in the frame. So I had to rotate the panel 1 master to make it stitch together properly. In the end, it all worked out. But, note to self: Check PA carefully before embarking on mosaics.

I stacked and stitched this in APP. Terrible UI, but great results from that application. (I still don't use WBPP for various reasons.) It took about three days, a day per panel, to stack at 1.2X drizzle, which is what I generally do for FSQ mosaic panels. 2X drizzle makes dealing with the mosaic so unwieldy. But no drizzle leaves me with little squares for the small stars and small features. I suspect that all APP is doing is drizzling at 2X and then resampling the final masters down to 1.2X. So just doing that manually might be a useful technique for those doing mosaics at a similar image scale using WBPP.

I think I was able to get a reasonable level of detail on the SNR and on MarSai 1, but certainly not as intricate as the amazing discovery image posted a year and a half ago. Constructive feedback is always welcome. Let me know what you think.

Despite the tribulations, this was a very enjoyable project and I learned quite a number of things from it. The FSQ is a mosaic monster for sure.

This involved 205 hours, 43 minutes exposure time:
Chroma Blue 50x50 mm: 543×180″(27h 9′) (gain: 2750.00) f/3.6 -10°C bin 1×1
Chroma Green 50x50 mm: 546×180″(27h 18′) (gain: 2750.00) f/3.6 -10°C bin 1×1
Chroma H-alpha 3nm Bandpass 50x50 mm: 535×300″(44h 35′) (gain: 2750.00) f/3.6 -10°C bin 1×1
Chroma Lum 50x50 mm: 720×180″(36h) (gain: 2750.00) f/3.6 -10°C bin 1×1
Chroma OIII 3nm Bandpass 50x50 mm: 526×300″(43h 50′) (gain: 2750.00) f/3.6 -10°C bin 1×1
Chroma Red 50x50 mm: 537×180″(26h 51′) (gain: 2750.00) f/3.6 -10°C bin 1×1

Equipment Details: Takahashi FSQ106 with QE reducer; 10Micron GM1000; Moravian C5a-100M; Chroma filters.

Name: Timothy Martin

Website or Facebook Profile: http://www.astrobin.com/users/AccidentalAstronomers/