From: "Good, Donald" 
To: 'Mel Bartels' , atm{at}shore.net
Reply-To: "Good, Donald" 


A little more detail is necessary.
1. When you say meniscus, do you mean that it has a spherical shape to
begin with, or is it flat?

2. There are 4 ways to support at the edge: a) Clamped - cannot bend
(rotate around edge tangent) or translate radially b) Hinged - can bend but
not translate c) Simply supported - can bend and translate d) Sliding - can
translate but not bend (unusual) You are probably not interested in a or d
because they lead to compound curves.

I have a book reference that don't have now, but can send later.
Unfortunately, my math is not up to the task without further research. Don

-----Original Message-----
From: Mel Bartels [mailto:mbartels{at}efn.org]
Sent: Thursday, January 30, 2003 10:14 PM To: atm{at}shore.net
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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