Re: [ATM] 6 inch F-8 to F-10

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

Richard F.L.R. Snashall wrote:
> For example, if the mirrors are f/8:
>
>     http://users.rcn.com/rflrs/schiefsp01-26y.atm   ATMOS input file
>     http://users.rcn.com/rflrs/schiefsp01-26y.len   OSLO input file
>     http://users.rcn.com/rflrs/schiefsp01-26y.txt   TEXT prescription
>     http://users.rcn.com/rflrs/schiefsp01-26y.zmx   ZEMAX input file
>
> The final system here ends up at about f/11.7.  Over the nearly
> two degree field, the Visual Strehl is above 0.87 (about 0.947
> in the field center).  Yes, it could use some figuring (SC = -3.24
> on the f/14 primary), but all-spherical still looks respectable.
> But, again, it has four mirrors -- perhaps a bit of an expense
> for a 106 mm f/11.7, unless some it comes inexpensively.
If, however, one can settle for a bit slower and allow some
vignetting (about 25% at the field edge), some might be saved
on the tools:

Title: schiefsp01-33x
106 mm f/14 Schiefspiegel
Primary/Quaternary Tilt: 10 degrees

Surf     Radius   Thickness   Glass  Diameter

   1   Infinity        1040               136
 STO      -2730        -440  MIRROR       108
   3      -1065         385  MIRROR       108
   4      -2730       -1050  MIRROR       108
   5       2730    1142.389  MIRROR       108
 IMA   Infinity                            43

Before anyone jumps too quickly the wrong way, the f/4.9 mirror
is the convex one.  The f/12.6 mirrors are all concave, even
though the prescription numeric values change sign.


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