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[ATM] Doublet


Let's run through your checklist...

     a) You're not really interested in making an ant burner; f/15 will
        be fine.

     b) But "normal" glass doublets don't light up your socks either.

     c) Fluorite is something you don't want to try right now, both for
        cost and workability reasons.

Assuming the simple crown glass a acquirable, this might fit the bill:

	http:/users.rcn.com/rflrs/d01-29x.len

This 150 mm f/15 doublet has better than 0.925 Photopic Strehl over the
whole 40+ mm diameter field (better than 0.99 in the center).  The
fluorocrown is at the cheapest level (with characteristics
that we expect from fluorcrowns, that is).

-- 
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Rick S.

http://users.rcn.com/rflrs