I had a chance to finally test the D500 using my old 50mm lens from my Nikon FM mark 1.
Actually I am pretty pleased with the result. Wide open this lens does produce fringing and coma but stop down from f/1.8 to f/2.8 things tighten up and get a lot better.
Here are some wide angle results:
Astro
This was stretched more, from a high Bortle9+ zone the image will always look terrible irrelevant of the processing done. Wide field and high Bortle don't really go together at all (it's the same image as above but I was trying to extract as much out of the M101 and M51 as I could):
Astro
Output from astrometry.net:
Astro
The PinWheel and Whirlpool galaxies are just smudges at this focal length (effective 75mm)
... once I have the Sigma I want to test it at 600mm and also try it out with a 2x teleconverter additionally
https://en.wikipedia.org/wiki/Pinwheel_Galaxy https://en.wikipedia.org/wiki/Whirlpool_Galaxy
For FoV calculation at 900mm and 1800mm I used the imaging section of this site:
astronomy.tools
Some more images:
Astro Astro Astro Astro Astro Astro
Overall, this will be a fantastic lens to do mosaic work with once I manage to get myself a Goto mount.
Currently all the sub frames were 6secs x20 stacked using Sequator then processed in Siril and RawTherapee. PixInsight would have done a better job overall but I haven't purchased it yet and the trial license has long since expired. I used ISO 800 which was a little too high for my area. I should have been at around 100 or 200!
Basically I didn't check the histogram as unlike my K1, the D500 doesn't allow you to have both grid and histogram on LV. It seems you need to do that by pushing the Info button and scrolling up and down...
Here's the very cute setup lol:
Astro 
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