To: atm{at}shore.net
From: tkrajci{at}san.osd.mil
Reply-To: tkrajci{at}san.osd.mil


> From: "Bianco Giuseppe" 

> I'm trying to understand whether Focault testing with a Couder mask
> could be a viable option to test a 310 mm diameter, f/2.5 mirror with a
> conic constant of about -3.
> Any suggestion on where to find documentation (theory, algorithms, etc.)
> on this issue?

I recommend the wire test instead of any knife edge test or test involving a mask.

Use a foucalt test rig, with the following details:  pinhole light source,
vertical wire (instead of knife edge), pin stick across the face of the
mirror (instead of mask).  The shadow pattern is different than Foucalt,
but the motion of the wire, and the math/analysis of zone readings is the
same as the Foucalt test.

Tom Krajci
Tashkent, Uzbekistan

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