Re: [ATM] Anastigmat

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

Richard F.L.R. Snashall wrote:
>
> Now, suppose you ignore the directions on the box... er...
> the current curves.  Grind both curves of the BK7 piece
> to the same curvature; also mate the F4 to it and put a
> small convexity on the flatter side.  Hard part: construct
> a 130 mm diameter cemented/oiled doublet to go with it:
Although, somewhat better and perhaps easier to re-build is to
simply reverse the crown element, changing only the flint, while
adding a slightly larger, but thinner, secondary doublet:

    http://users.rcn.com/rflrs/Ptz10-45x.atm   ATMOS input file
    http://users.rcn.com/rflrs/Ptz10-45x.len   OSLO input file
    http://users.rcn.com/rflrs/Ptz10-45x.txt   TEXT prescription
    http://users.rcn.com/rflrs/Ptz10-45x.zmx   ZEMAX input file

At f/8.545, this is somewhat longer, about 2346 mm.  The
field is thus also smaller, 0.693 degrees.  Visual Strehl is
now 0.6642 at the field center and 0.6548 at the field edge.
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