From: 
To: "Mel Bartels" ,
        
Reply-To: 



Am I missing something? I'm sure many of you know this but I am going to
take the plunge anyhow (gulp).

It is a forth-order polynomial of the form

   y = a0 + a1* x**2 + a2*x**4

It so happens that the equation of a Schmidt corrector plate is of the form

   y= b0 + b1*x**2 + b2*x**4

The a's and b's are constants. Bernhard Schmidt discovered this
relationship in the early 1900's enabling him to make many fine correctors
using the vacuum method. It is all covered in ATM Book 3.

Tom Stokes

----- Original Message -----
From: "Mel Bartels" 
To: 
Sent: Thursday, January 30, 2003 8:13 PM Subject: ATM deformed mirror shape


>
> I was asked in a private email the derivation of the deformed shape where:
>
> 1. glass considered thin meniscus of constant thickness (ex. 12 inch
> diameter, 1/4 inch thick)
>
> 2. glass supported at extreme edge (supported inward better???)
>
> 3. glass facing upward towards zenith
>
> What is the resulting shape?
>
> Years ago Tom Lum and I derived this - and I cannot remember for certainty
> if the shape is parabolic or spherical.
>
> Can anyone take a stab or point to articles?
>
> TIA Mel Bartels
>
>

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