Re: [ATM] Another flat-field anastigmatic aplant

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

vladimir wrote:

>Richard F.L.R. Snashall wrote:
>
>
>>Before it gets to one-fifth of that, the unvignetted diameter at
>>the hole in the primary is larger than the secondary size.  Just
>>curious: what would you suggest as the final size for that hole?
>>
>
>Secondary size is small to begin with (less than 17% the primary 
>linear size in this particular system). Even that small, it is probably 
>large enough to accomplish its baffling role, due to close proximity 
>and small diameter of the front baffle opening. As such, it is not a 
>factor in the effective c.obstruction of the system. The primary central 
>opening would be determined as a compromise between the max field 
>diameter obtainable with the largest acceptable size of c.obstruction. 
>If ~1-degree fully illuminated field (and somewhat wider useable field) 
>is large enough, central opening somewhat larger than 0.4D 
>should do.
>
Now, if I've done everything right, this one may work.  I don't
know if anyone will like the geometry, though:

Surf      Radius    Thickness    Diameter          Conic

 STO    Infinity     8.685113         400              0
   2   -2304.134    -924.4531         400      -0.690765
   3   -643.6788     2162.813    95.11423              0
   4   -874.9134    -639.3422    303.9729     -0.4081003
 IMA    Infinity                 31.88004              0

The diameters here are the unvignetted diameters.  The central
hole size is the same as the secondary.
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