ATM - Re: ATM Null test for Cass Secondaries

[Richard Schwartz <richas@idt.net>]

Two comments...

The use of the letter "e" to describe the conic constant... is "e" the
eccentricity, or is it the Schwartzchild constant?

Mirror makers are urged to exercise caution when using the hotwire as a
knife edge.   Contamination on the wire may cause nonuniform
illumination of the optical surfaces, so take care to avoid soiling the
wire with burnt cornea.

. . . Richard
---------------------------------------------------------------
Date: Tue, 19 Jan 1999 14:41:21 -0500 (EST)
From: Ric Rokosz <bz737@freenet.toronto.on.ca>
Subject: ATM Null test for Cass Secondaries

There is an interesting article in SPIE vol. 1332 1990 pp107 - 114 that
outlines a null setup to test aspheric convex secondaries that uses a
spherical concave mirror as the nulling optic.

There some typo errors in the article,but Peter Smith was generous
enough
to work through the example in the article using Zemax and came up with
the
correct numbers.

The formula to find the RC of the nulling spherical mirror is:

            2r(e)^1/2 / e+1    where r is the rc of the secondary mirror

                                     e is the conic constant