Re: [ATM] Constraints on design

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

matt wrote:

> 
>
> Richard,
> I would be interested too in your prescription as a starting point and
> comparison with my goal.
> I found references to professional telescopes 24" aperture and f/6 overall
> with Klevtsov style correctors , so it is possible to reach a good design
> with it .
> best regards,
> matt tudor

The first design I found was:

    http://users.rcn.com/rflrs/rc2-15x.atm
    http://users.rcn.com/rflrs/rc2-15x.len
    http://users.rcn.com/rflrs/rc2-15x.txt
    http://users.rcn.com/rflrs/rc2-15x.zmx


This particular choice of triplet glasses aims toward the spherical
secondary at that speed (f/10.1).  I have re-optimized the BFL and
focal surface for best visual performance, but have commented in the
BFL for wide-band (i-t) imaging.

By changing the short flint to the Schott equivalent (N-KzFS4), the
triplet aims toward a spherical secondary at the faster speed (f/9):

    http://users.rcn.com/rflrs/rc2-16x.atm
    http://users.rcn.com/rflrs/rc2-16x.len
    http://users.rcn.com/rflrs/rc2-16x.txt
    http://users.rcn.com/rflrs/rc2-16x.zmx

The triplets here look somewhat different, even though the special
short flints are supposed to be equivalent.  There is, however,
more difference in the IR and UV than in the visual and these
are optimized for the imaging.

I haven't had much time to investigate these further.  One of the
open parameters is still the separation between the Schmidt corrector
and the secondary; I somewhat arbitrarily chose 24 mm.  The other
free parameters are the secondary size (I chose 25% of the primary
size) and the focal distance behind the primary (I chose 75% of the
clear aperture).  I think modifying these parameters will change the
aimed speed for each triplet.

BTW... that leaves me with my original question... "how much space
is needed between the corrector and the secondary and how would you
attach them?"

Hope these give you some ideas.

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