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Re: [ATM] All Spherical Telescopes



Richard F.L.R. Snashall wrote:

>Hugues.Laroche@ses-astra.com wrote:
>
>
>>In the sub-aperture corrector branch of this zoology ;-) you may also
>>count the Icarus design:
>>
>>http://members.tripod.com/mipan/IcarusHome.htm
>>
>
>added the relay elements in the path, ending up with f/-12.  It
>doesn't quite get to diffraction limited.  I wonder if some other
>tweek would push it over. I like the fact that the lens pairs are
>mirrors of each other (except the spacing).
>
By increasing the base focal length and squeezing out some of the off-axis
performance:

Surf      Radius  Thickness    Glass  Diameter
 OBJ    Infinity   Infinity                  0
 STO    Infinity   8.339773                600
   2       -5400      -2079   MIRROR       600
   3     -2173.5       1449   MIRROR  149.6556
   4    Infinity   179.4882           38.57416
   5    Infinity          9    N-BK7        60
   6      -77.85    10.9142                 60
   7   -69.63015        4.5       F2        60
   8   -124.6395   415.9049                 60
   9    96.19802        3.5       F2        50
  10    52.58412    9.88263                 50
  11       62.28        8.2    N-BK7        50
  12    Infinity    453.292                 50
 IMA   -246.4339                      41.73529

The two N-BK7 lenses can be satisfied by  OptoSigma 
<http://www.optosigma.com/> lenses
011-2990 and 011-3770.  The central visual Strehl is 0.806.

A later upgrade could be:

   4    Infinity    127.483           38.57426
   5    905.8383        4.5  N-KZFS4        60
   6    137.5719   1.199993                 60
   7    153.6871         10   N-FK51        60
   8     -166.53   462.9902                 60
   9    181.0594       10.5   N-FK51        55
  10   -89.31551    15.0806                 55
  11   -68.87209          4  N-KZFS4        55
  12   -166.7016   459.2385                 55
 IMA   -244.2171                       41.8301

The central visual Strehl here is 0.950.  The edge visual
Strehl is still 0.920.




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