The flatness, not neccesarily so much, but quality of the flat does matter and should be tested for smoothness to make sure it is free of zonal errors. That's coming from Peter Ceravolo and it doesn't get any better than that.
Actuall, Daniel, this reference you mentioned above came from me. I pointed you to the Peter Ceravolo documentation in another thread as its what I use it as a reference to construct my interferometer, and its mentions optical flats and the need for regularity rather then absolute flatness.
I compare telescopes against others. Would be nice if you guys were able to do the same but I understand it’s hard when the weather doesn’t allow. Regardless, I like what you are doing here and I think it’s very nice that you are trying to help others learn to test their telescopes. It’s better than not doing anything at all with bad weather.
I would venture to say that most of the telescopes you test are imported from China. The sample to sample variability has to make testing telescopes against each other a somewhat futile process. With DPAC, that goes away. You test the telescope against itself. Its the perfect Null test.
Whats your reference telescope and has that been tested? Is it with you on every test? In DPAC you don't need a reference telescope.
In every example, I have been able to have my star test results in with what I see on the DPAC bench. Its a beautiful thing.
Edited by peleuba, 24 September 2018 - 12:48 PM.