Re: [ATM] Aplanatic Gregorian (was: 25" mirror possibilities)

[Jarvis Krumbein <jkoptic@juno.com>]

Mike, if you fold the system very near the focal point of the primary you
can have a faster system with a very small obstruction.  My own proposal
is for an f8 system with an obstruction of less than two inches with a
twenty inch primary.    In addition, baffleing is simple and foolproof.

Jarvis Krumbein

On Thu, 25 Nov 2004 19:53:08 -0500 Michael Lindner <mikell@optonline.net>
writes:
> On Thursday 25 November 2004 02:45 pm, Richard F.L.R. Snashall wrote:
> > Aplanatic with only 21.5 percent secondary size at 40+ mm field 
> size.
> 
> Uncle! In my defense, I wasn't thinking about such a slow system, 
> and if you 
> compare secondary size to any other cass you will find it's quite a 
> bit 
> larger. However, I apologize unequivocally for making 
> generalizations.
> 
> Clear(er) skies.
> -- 
> Michael Lindner
> http://www.starastronomy.org *** http://home.att.net/~mikel
> http://www.atmsite.org *** http://www.atmlist.net
> 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


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