[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: [ATM] Mirror Tester

Mahmood,

> I am constructing my mirror tester (Foucault+Ronchi), and I have a dial gauge which has a total travel of 10 mm. Will it be sufficient for testing 6 inch F/9 mirror.

Your tester will need to move the distance of the sagitta (depth of
curve) of your mirror for a moving-source tester, or twice the sagitta
for a fixed source tester.  The formula for the sagitta of a
paraboloid is radius^2/(4*focal_length).  In your case, a moving
source tester would need to move 1.06mm, and a fixed source tester
2.12mm.  That's well within the 10mm travel.

--
Steve Koehler
_______________________________________________
ATM mailing list http://www.atmlist.net/