Re: [ATM] A two way null test for convex hyperboloids

[Michael Peck <mpeck1@ix.netcom.com>]

At 04:35 4/6/05, Mauritz Andersson wrote:
>But I thought the problem for both the Schmadel test and the reverse version
>is testing and verifying the convex spherical surface?
>/Mauritz
>

Yes, that's a "problem," but there are simple solutions. For a one time 
project the easiest is to use a concave test plate, which you can make 
simultaneously with the reference surface by using any old piece of glass 
as a tool.

So, which is easier? Fabricating mating spheres, then figuring a 
hyperboloid with an autocompensating null test. Or making two hyperboloids 
simultaneously, trying to iteratively approach the desired surfaces. I have 
no idea of the right answer, but I know which one I'd be more likely to try.

Anyway it appears you've discovered a generalized version of the Schmadel 
test. You can pick any conic for the back surface and find a solution for 
it's RC and source-lens distance providing a null test. I don't know if 
you'd still have a null in the reverse test though.

Mike Peck


------
Michael Peck
mpeck1@ix.netcom.com

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