[ATM] Preannouncement (ECDK)

[Richard F.L.R. Snashall]

Richard F.L.R. Snashall wrote:
> In honor of tomorrow 
Seriously, though, I surmise that R&vV indicates that an SCT
with spherical primary and secondary will end up with some
coma as well as having a curved image surface.

Then, too, that you cut your corrector out of a square piece
of glass and started the process by making the octagon.  Why
not do something with those triangles?

For example (508 mm f/10, double-sided corrector):

    http://users.rcn.com/rflrs/rc6-88x.atm   ATMOS input file
    http://users.rcn.com/rflrs/rc6-88x.len   OSLO input file
    http://users.rcn.com/rflrs/rc6-88x.txt   TEXT prescription
    http://users.rcn.com/rflrs/rc6-88x.zmx   ZEMAX input file

If I've done my arithmetic correctly, the diameter of the
maximal blank that can be cut from the triangles is about
18% of the diameter of the corrector cut from the square.
This design fits in that 18%.

This uses some of those triangles, corrects the coma, and
flattens the field some.