From: "James Lerch" 
To: "ATM List" 
Reply-To: "James Lerch" 


Greetings All,

I'm looking for a formula for generating perfect longitudinal knife edge
readings for Foucault tests.

Parabolic mirrors are easy enough (I've got that working already)  What I'm
looking for is complete formula that will calculate the longitudal readings
for mirror have a non-parabolic conic constant.

BTW, when I say 'Perfect' numbers, I don't actually mean
"Perfect" :) Longitudal zonal readings that will spit out
"2-9s" for a strehl ratio would be fine!

For reference, I'm currently using the following formula to calculate
perfect longitudinal zonal readings

For each zone radius, (moving source tester) longitudinal reading =  Z^2 / 4F

Where Z = center radius of Zone & F = Focal Length

For a fixed source tester, I just multiply above results by two.  So far
this works out good enough for the intended purpose, but only for parabolic
mirrors.

Thanks in advance,
James Lerch
http://lerch.no-ip.com/atm

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