From: "Richard F.L.R. Snashall" 
To: ATM 
Reply-To: "Richard F.L.R. Snashall" 


Two examples of triplets with a split field corrector are given.  Each is
150 mm f/8 with a 42.8 mm flat field (big enough for a 2" eyepiece or
35 mm film), and a BFL forced to 225 mm (allowing enough space for
whatever). Two of the less expensive Lanthanum glasses are used.  These
have approximately the same refractive index.  This would allow for the
same index matching oil to be used on both sides of the central Fluorcrown.

        http://users.rcn.com/rflrs/calcn-27x.len
        http://users.rcn.com/rflrs/calcn-30x.len

The first is optimized for Photopic use, while the second is optimized for
Photographic use.


--
Rick S.
http://users.rcn.com/rflrs

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