I'm glad you liked it. Not everything with optics is complicated. If you're going to wonder about your optics, you'll have to do some testing unless you can hire someone to do ti for you. It's your choice.
Incorrect shims would result in more spherical aberration. This would manifest itself as curved Ronchi lines .Again, you'll have to do find what Ronchi patterns mean what. There are many examples to be found online. I already gave you one source.
Basically, your test will require a Ronchi screen (100 lines/inch is a good general-use frequency), and a good high-power eyepiece. The eyepiece would be used in place of a Ronchi screen to test for image quality. The Ronchi screen would tell you if you have astigmatism, spherical aberration etc. The eyepiece will show you
what a star image would look like,etc.There are many causes of astigmatism, coma, spherical aberration, chromatic aberration, etc. Shims may be one of them.
For chromatic aberration, use a white LED as a light source. For correction of the lens as a whole use a green LED.
If you know how to use the knife edge (as in a Foucault test) it can give show you the figure of the wavefront very clearly. You can achieve that by using only one band of the Ronchi test with somewhat less clarity. Ideally the wavefront should present as a flat disk, or straight Ronchi bands (with 3 to 5 bands max) showing. You may be surprised how many optics fail this simple test.This one is clearly unacceptable.
I tested a 5-inch f/9.4 doublet and found out that the lenses were inverted in the cell.
After turning them around, the objecitve turned out to test excellent. (When judging the results, don't forget that DPAC shows the errors doubled)
Another objective showed clear coma on-axis due to a uneven spacers.
Edited by MKV, 29 June 2019 - 02:38 AM.