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[ATM] How to get "b" and surface figure from Texereau style datapoints???
Thanks to all for the help to date on this 8" f/6 I am trying to create!
After my first Ronchi and Foucault glances I thought I might be ready to parabolize, so I began trying that. The figure started to look kinda odd, a bit like a bowler-style hat with a dent in the crown - the brim would be my turned up edge. (The TUE existed before I started this figuring.)
So, thinking I am getting ahead of myself, I have gone back to Tex's spherizing stroke, 1/3 W, MOT, with 1/6 lateral overhang per side. The figure now LOOKS much better through the tester, but after crunching the 4 zones of data, I am beginning to wonder if I have a hyperbola or something like it.
Tex talks all about the deformation coefficient, "b," and what to do in the case of hyperbolas and any other errant figure. The one thing he forgets to mention is how we are supposed to know what "b" is based on a 4-zone Foucault test. I have plotted his wavefront error graph, but that still does not equate to surface figure. I'm thinking Sixtests might be the answer, but based on an article I read, it seems I would need a ton of zone data points to really get a good idea of the surface shape.
By the way, according to my numbers for the wavefront error (using Tex's procedure), I am about 85,000 wavelengths (!!!) away from what Tex calls the best fit wavefront. I am hoping that I either have a simple error in my calculations, or that polishing works such that this ridiculously huge-seeming error goes away very quickly once the surface gets more uniform. ( Latest data is supplied below, if any interest, using Tex's notation and variable names).
Thanks for the ideas...
Jay
ZONE1234hx1.4152.563.3353.984375hm0.70751.98752.94753.6597(hm^2)/R0.00490.03860.08490.1309hm/4f0.00350.00970.01440.0179D1,2 = Avg. (D1, D2)0.42540.47760.5340.5243D1,2-eqlztionK0.00710.05930.11570.106Big-Lambda sub C0.0020.0210.031-0.025Lambda sub f x 10^50.76320.09244.321-44.632Lambda sub f / Rho0.0421.1012.429-2.446u x 10^4149.19513928.7578666.542-8727.5
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