From: "Bob May" 
To: "atmlist" 
Reply-To: "Bob May" 


Figuring lenses?  You just make them spherical and you can test the
spherical against a parabolic mirror setup as a light source. What makes
things even easier is that a turned edge is hidden by the mounting of the
lens rather than actually being used as a mirror is.  In addition, good
spherical surfaces are usually automatically generated by the proper
actions on the lap.
What makes things even easier is that one of the surfaces can be used to
take out any minor errors with the other three is so desired. FWIW, I'm in
the process of making a doublet at this time and have a preliminary polish
on the four surfaces and am ready to test for color errors.
Bob May
http://nav.to/bobmay
bobmay{at}nethere.com
NEW! http://bobmay.astronomy.net

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