Re: Testing old mirrors


Dale and All,
since May 4-th and until yesterday I had a problem with unpredictable results with DFTF when testing old mirrors. The results were different compared to other people's tests and depended on the "blue filter" size as I mentioned in the first post.
With the help of Alex I realized that I am not outlining the Central Hole (!) counting that I have already set it up in the "mirror configuration" ....
Why? - a good question, I usually do many tests per day, but all of the objectives with no obstructions.
Well, now all problems are solved and I am back to tests.
BTW. While having issues with DFTF, I returned to working with the AtmosFringe again, which was helpful since results were repeatable.

Attached are tests of the primary mirror of the Gregorian telescope by Amici. the Atmos test in the middle, DFTF on the right (via Alex).
Tests were done before and after focus - BF, AF.
Thank you all for trying to help me, special thanks to Alex!

                                                    AtmosFringe                     DFTF
1 Before focus Strehl / Conic       0.774 / -0.733                   0.791/ -0.649
2 After focus  Strehl / Conic         0.785 / -0.736                  0.783 / -0.548

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