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Re: [ATM] Finder

Richard wrote:
> Looking altogether more doable now :)
I spent some time scrounging through some surplus lens sites.
I did not yet find a match that worked for a larger size.  I
did, however, find [SS == Surplus Shed]:

Title: Ptz08-14kx
48 mm f/6.367 Refractor Using Surplus Lenses
VS: 0.8157 at +0.0084 mm shift
VS: 0.4403 at 3.93 degrees
Min: 535.022 nm
Sugg: SS L7021 (50 mm 125 mm f.l. isoconvex)
Sugg: SS L4521 (47.6 mm 154 mm f.l. planoconvex)
Sugg: SS L8032 (43 mm -71 mm f.l. isoconcave)

Surf    Radius   Thickness   Glass   Diameter
 OBJ  Infinity    Infinity                  0
 STO  Infinity   -2.264422                 48
   2   128.317         7.9   N-BK7         50
   3  -128.317   0.2567538                 50
   4  -128.317           2    N-F2         50
   5  Infinity    188.4935                 50
   6    79.883         6.6   N-BK7       47.6
   7  Infinity    30.06225               47.6
   8       -74           2   N-BK7         43
   9        74    49.63222                 43
 IMA  405.5189                       42.77845

All of this assumes that the actual glass type in these
lenses is BK7/N-BK7 and my estimation of thickness, etc.
is correct.

The third lens is not AR coated and the Strehl doesn't quite
hold up across the field as much, but, for $4 per lens (plus
making the N-F2 lens, of course)...



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