Re: [ATM] Alternative Petzval Design

["Richard F.L.R. Snashall" <rflrs@rcn.com>]

Richard F.L.R. Snashall wrote:

>
>By leaving a bit of C-F lateral color difference (i.e. the C line does
>not precisely match the F line w.r.t. lateral color), and shifting the
>one glass -- here's a design that can have the second doublet cemented
>or oiled; the expansion difference is small.
>

Not necessarily... I wonder if there's an extra degree of freedom around
here:

288 mm f/7.5 Petzval
VS: 0.5507 at 0.0384 mm
Min: 546.270 nm

Surf     Radius   Thickness    Glass    Diameter

 STO   Infinity   -8.816088                  288
   2    1180.44        31.2    N-BK7         300
   3   -1180.44       4.824                  300
   4   -1180.44        21.3       F2         300
   5   -24595.2     1707.75                  300
   6    535.104        18.6    N-BK7       139.2
   7   -535.104        11.1   N-BAK4       139.2
   8     882.54    697.6536                139.2
   9   -2199.72      0.0384               42.192
 IMA   -2199.72                           42.192

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