What are these rings on my startrail photo?

OK, better if you just look at the photo as I'm not sure how to explain it.
What are the rings making it look like I've taken a photo of a monitor???
Does the same in Photoshop and StarStax regardless of how I try and process them.

Any advice would be greatly appreciated as it's highly irritating.

Thanks

Did you take a photo with your camera of the monitor screen or did you do "Print Screen" and save as a jpeg ? Hard to really tell from the above image what all rings are you talking about . I do see a small circle of about 3-4 rings but I don't know if that's from your monitor or camera lens ?

almost looks like newton rings lol! would be interested to find out what it is... did you have any filters on the lens?

Hrm,

I see the grid in your image, it's moire pattern.

It's a result of the stacking software and the processing bringing out the grid pattern (high frequencies from the Bayer matrix) from the stack.

Try processing the sub frames with your typical workflow as a batch, then stack them. Another option is to downsample it and then stack and see if the pattern remains.

Very best,

Thanks all!
I've no idea what it was but it had something to do with the post processing in Lightroom before exporting them.
No idea why as I didn't do anything differently.

MalVeaux - thanks for putting a name to it, made it much easier to Google!

I'm assuming this is a stack of many images and not a single image (based on how far the stars moved).

I'm wondering if this isn't an artifact of moiré from the image registration (aligning the frames for stacking).

If I remember correctly I think it was 32 photos altogether.
However I re-ran the post processing again, this time I didn't do any cropping and only made slight adjustments to the exposure etc and it came out perfectly without any moire.

Never happened to me before so it must have been an adjustment I had made in while in Lightroom before exporting them.