Re: [ATM] A new flat-field anastigmatic aplant?

["vladimir" <svla@isp.com>]

Hi Heiner,


> I tried it in OSLO. Is it this, what you meant?
> http://www.otterstedt.de/atm/tmp/vlad.len


I would say so, except that ATMOS gives the f.l.
(best focus location) as 1097.157mm (vs. 1097.2mm  with OSLO, which may have 
been rounded off).

> interesting idea, but I'm a bit concerned about the
> obstruction of the light cone on its way back from
> the tertiary to the focal plane. Especially because
> the secondary is reflective on that side...

That is a good point. There is a possibility of some
unwanted reflections, and it would have to be dealt
with as a part of baffling the design. I'm inclined to
think that it can be solved satisfactorily, since the
secondary/tertiary configuration is very similar to a
particular form of inverse Cassegrain (specifically,
Schwarzschild concentric anastigmat, also using
two spherical mirrors) which is presented as a viable
design (except that is aperture inefficient, with the
secondary being up to several times larger than
primary mirror).

Btw. does OSLO give similar field performance for
the given input? ATMOS gives about -20,000mm
field curvature and a sub-micron spot that doesn't
change in size as far as 1 degree off-axis. But Rutten/Venrooij's
Raytrace and Winspot both show
some coma/astigmatism for the same input, and need
input changes - not identical, and likely not at the optimum possible -
 in order to have them reduced to bellow
5 microns 0.5 degrees off axis. Which software to believe to?

Vlad 

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