Re[2]: [ATM] Constraints on design

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

Hi Richard,

Wednesday, April 27, 2005, 11:30:44 PM, you wrote:

RFLRS> Actually, only ATMOS indicates that this as a poor design.  Both OSLO
RFLRS> and ZEMAX indicate visually diffraction-limited performance.  The
RFLRS> constraints are that the primary is spherical while the secondary
RFLRS> is parabolic with a BFL of 3/4 aperture.

Yes, I meant primary, sorry, although the cost of materials and
labour on making that huge optical corrector must outweigh the
hyperbolic figuring of the mirrors.

As for difraction limited performance, I see a best case
geometric spot radius of 20.19um and an Airy disk of 13.8um.
What do you see?

I'm not meaning to criticise Richard, I just don't understand
the thinking behind this design. About the only thing that would
make me consider it is if someone gave me a whopping great disk
of BK7 for free and even then it would be a difficult decision
between that and a standard RC. Actually, I'd sell the BK7
and buy the blanks for the mirrors with it and have a good
holiday with the change :)

-- 

Best regards,
 Richard



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