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How can I make a flat mirror? Ronchi screen, where to get?
I am looking at how to test a mirror and I would like to build an autocollimation test rig.
The one I have read up on had a round flat mirror. Would it make a difference if the mirror is square? Surely a square one would reflect the round image of the Primary as a round. How is a mirror made flat?
I have tried to print a ronchi screen on the laser printer. It did not come out as well and everyone that makes a mirror would use a ronchi. Where can I get one at a reasonable cost.
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