Re: [ATM] Gimbaled Secondary mirror

[Richard <cnc@cncservo.co.uk>]

Hi atm,

Thursday, June 30, 2005, 10:15:21 AM, you wrote:

aho> I've run this through OSLO and CODEV and I don't see any appreciable change
aho> in aberration for the various back foci.

I have to say I'm with Dave on this one. I've ray traced the
design spec on your web page and I find moving the secondary by
20mm does reduce the back focus from 640.5mm to 449.5mm, but at
the expense of reducing the Strehl from 0.983 to 0.614. That
said, I can't duplicate your stated F/# or focal length from
your spec either, so I may have made an error.

No offense intended, but it seems odd to choose a classical
Cassegrain for a professional telescope these days. What is the
reasoning behind a clasic cassegrain as opposed to, for example,
a Ritchey Cretien?

-- 

Best regards,
  Richard in the UK



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