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Need Help With First Time Foucault Test

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Posted by Bill Wetterau on April 17, 2002 00:03:55 UTC

This is my first attempt at makeing and testing a mirror, so I've been trying to learn as I go along. I've built a tester like the one in the Texereau book, and I'm trying to use it on an 8" f/8 mirror blank I've made. I just don't seem to be able to get things set so that the mirror darkens evenly as the knife edge is inserted. All I see is the knife edge itself passing across my vision. I think I understand the geometry OK, and I've used the tester with a Ronchi screen, and gotten images that make sense that way. How far behind the knife edge should my eye be? Am I just making some simple dumb rookie mistake that someone experienced can help me with? Thanks.

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