I am puzzled by seeing two main "sizes" of Newton's rings posted in photos here -- one type is about a dozen large shadow bands equally spaced (by eye) across an image. That is the type I get on my LS60T/ASI174MM. I need massive amounts of tilt to get rid of them -- the full range of my ZWO tilter. The other sort is hundreds of narrow bands, again seemingly regularly spaced. I am wondering if those need much less tilt than I have to use. These two types don't seem to vary between different image scales, though I have not done a detailed study.
I am familiar with the physics (https://en.wikipedia.../Newton's_rings) showing how the bands of the rings change in size from the origin (center), but at the outer areas, I presume it approximates to the regular pattern (dozen or hundreds) I'm seeing in photos.
1. Is that true, that what we are seeing here is *apparently* regular spacing, but that's just because the distance from the origin (wherever that is in this scenario?) is relatively great?
2. Are the two size types I'm referring to just different manifestations of the same thing and actually there's a continuum of sizes -- some of us get the big "dozen" fatter ones, others get the 100s, and still others get everything in between?
3. In night astrophotography, I'm aware of how you can calculate what the cause of an optical aberration is by its size -- for example, you can guess what might be causing a donut around a star such as a reflection from a filter or whether a dust mote is on the sensor glass or some other part of the system. Do the different scales of Newton's rings tell us anything about what the underlying cause might be in our setups, and whether there is a better adjustment we can make to address them?
Meanwhile, I will be working on flats, which I'm familiar with from night astrophotography, and trying to apply that to my daytime repertoire...