I recently shot the Andromeda galaxy with my full spectrum Nikon D5600 which turned out to be ok, although it was more of a test.
Since there is that concentric ring issue with the Nikon cameras (some claim they do not, but they do), Mark recommended me to try the lowest ISO and use shorter subs.
Well, it worked for the Andromeda Galaxy, but appearently doesn't work for the Pleidaes . I start to see a pattern, where brighter objects will cause the Nikon sensor (or internal processing) to create those ring defects in the images.
And no, the image is not overstretched or calibrated badly. The rings are there int he subs.
I am trying to figure out whether the choice of a telescope (Newtonian vs refactor) also matters, but since I do not get rings using a 533mm or even my Pentax K70 DSLR using a Newtonian, I doubt the choice of the telescope matters.
So, I'm sure more tolerant people wouldn't care, but I just cannot unsee it, once I see it.
I'm just not sure if I should keep using this camera. I bought it relatively cheap as used ($250), to get an APS-C sized sensor in my arsenal.
BUT
I get rings if it's a short exposure and low ISO as well as longer exposure with higher ISO and the mix of those. It just doesn't matter what I set it to, the rings will make an appearance.
I used ISO100 and 20 second subs for this:
Here is with moderate stretch
to demonstrate the ring I over stretched it
I wish there would be a "ring remover" script in Pixinsight, lol!
Just like there is Canon banding removal script.
Edited by unimatrix0, 18 December 2023 - 03:31 PM.