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Sagitta
Still polishing & beginning to test but would like clarification.
I have measured the sagitta at 6.02mm which gives an F of 2.6 and ROC of 1298mm.
When the mirror is in the test stand the reflected light comes to a tiny circle at approx 1254mm giving a differential of 44mm. Yellow paper not sitting flat but was necessary to get an image.
My conclusion is that the reflected light measurement is correct and that my sagitta measurement is wrong.
Has anyone had experience with this?
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