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


Fringe errors can be of the pure spherical form or of some more complex
form.  Spherical error is merely the difference of radius of the two
surfaces and will be of no concequence.  If you have only 2 rings when the
two surfaces are not wedged, you are very close to the desired curvature
and it would be a decent time to stop.  The shape of the lines will
determine if the surface is indeed a sphere and, if so, it is time to quit
and get it aluminized.
You can then finish up any errors on the surface with changes to the
primary to compensate.
Bob May
http://nav.to/bobmay
bobmay{at}nethere.com
NEW! http://bobmay.astronomy.net

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