Re: ATM Spider Design

[epabcc@epa.ericsson.se (Bratislav Curcic)]

Bob Goff wrote :

> I vote for no spider diffraction.

So do I. But my problem is that properly made spider for say a 16"
scope is FAR easier to make than a 18" window. Not to mention the 
price of the optical glass slab.
Besides, at this stage I know that making an excellent mirror of that
size (say 12-16 in) and moderate f/ratio is within my grasp. I don't
feel as confident that WINDOW I'd make in 16" region could be of similar 
wavefront quality as I don't have any means of reliable testing for it 
(I don't - yet - have Zygo ;-) .


Bratislav