Re: [ATM] Help with Richfield mirror

[Jim Burrows <burrjaw@earthlink.net>]

At 2004-07-19 07:15 -0500, M Robinson wrote:

>I have been working on a 6" richfield mirror with a ROC of 44.65".
>
>I use TEX program and I think that the middle zones are too high but I am 
>not quite sure. I have done several easier mirrors and have done fairly 
>well. I am having trouble understanding what the problem with this mirror is.
>
>If anyone can help me I would sure appreciate it! The data is below
>
>...
>
>Foucault tester light source moves with knife edge.

Sixtests says you still have a ways to go:  surface RMS=40.3 nm, Strehl 
ratio = .428.  The best-fit conic b=-.922 says the overall correction is 
pretty close, so I'd suggest Texereau's "standard" 1/3 stroke with 1/4 "W" 
to smooth it out and keep the correction from going down - most of the RMS 
is coming from zones in nm: -100@center, +50@35 mm, -50@55, 100 TUE.

It could be the "zoniness" is an artifact of Foucault test, which is hard 
to do on an f/3.7 mirror.  You might try the caustic test or the lateral 
wire test on this fast a mirror.

         -- Jim Burrows
         -- mailto://burrjaw@earthlink.net
         -- http://home.earthlink.net/~burrjaw
         -- Seattle N47.4723 W122.3662 (WGS84) 

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