Mike, I heard back from Ivo. He came up with a way to clean up the streetlight using the Wipe module. He used the "Uncalib2" preset and reduced the gradient aggressiveness to 25%. It did a great job of removing the streetlight, but dulled down the colors in the target quite a bit. I have played around with various settings and processes today and haven't been able to get anything much better out of it.
About the Nikon color rings, here is what I got from the "Color" display in "Wipe" when I used 8K flats:
rings in Wipe.JPG
As you can see it was pretty ugly. I used bias frames to calibrate the flats, I am wondering if dark flats would do a better job as the exposure was 1/6". I am going to give it a try after I shoot the dark flats and see if it does any better. I used dark flats with the 1/4" flats for this process and they did a better job of cleaning the dust bunnies and removing the rings.
Thanks for taking the time to work through the streetlights with the Filter module, your result was more natural looking than my first pass at it.
I have been reading several of the threads on the rings over the past few days and will continue to do so. I shot this data at ISO 400 and was hoping to go down to ISO 200 the next time out, but I admit to being a bit fearful of it now. We'll see how the experiment(s) go over the next few days.
Wow, like a roll of Lifesavers! My NGC1499 was like that, and a few others.
For bad rainbow rings I usually keep the standard preset in Wipe, move the second slider (falloff or something like that?) all the way to 100, and the aggressiveness to whatever level short of 100 I can get away with. Often 90-95. Worst case I will use the synthetic flats (even though I use flats) and/or the uncalib, to see if it helps.
Sometimes I'll wipe a little less, 85-90, if after that there's only one far-flung ring left - which seems to usually be yellow or blue - and I can then either crop it out, or select it easily in mask by color/brightness and then use filter->reject. Poof, gone.
Yeah after today's rainbow ring developments I'm looking forward in trying to dial in Mark's recommended ADU levels for the light frames. Seems so low! But I'll give it a try. Week of rain though, so I may just browse my HDD to see if I have any old data that was unintentionally underexposed.
Me too on the bias. After reading up a bunch on DSS, I've just been doing dark flats. I had been throwing everything in there.
Edited by Mike in Rancho, 26 January 2021 - 01:01 AM.