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Re: [ATM] N-KZFS-4



Richard F.L.R. Snashall wrote:

>
>The BAK4 design is quite similar to the
>following design for a 125 mm f/12 refractor:
>
>Surf      Radius  Thickness       Glass      Diameter
> OBJ    Infinity   Infinity                         0
>   1    658.4885   11.52753      N-BAK4           130
>   2   -6780.276   23.12584                       130
> STO    Infinity   6.881435                  121.6813
>   4   -272.3951   14.15397          F2           130
>   5   -143.8506          8     N-KZFS4           130
>   6    449.4114   19.88205       N-BK7           130
>   7   -248.3615   1501.053                       130
> IMA   -947.4752                             26.02613
>
>The stop is placed coincident with the front mounting of the
>triplet; its diameter calculated to provide the 125 mm effective
>aperture.
>
But:

Surf      Radius  Thickness       Glass      Diameter
 OBJ    Infinity   Infinity                         0
   1    1553.713   11.77975      N-BAK4           130
   2   -874.3206   37.13928                       130             
 STO    Infinity   9.911175                  119.7946
   4   -185.9477          8     N-KZFS4           130
   5    192.3444   16.16369          F5           130
   6    1279.523   20.27615       N-BK7           130
   7   -180.3021   1517.568                  128.0278
 IMA   -1440.639                             26.02212

does about as well (maybe a tad better across the field) with
shallower curves.  However, it also does not match up well with
the in-hand glass.
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