Re: [ATM] RE: 25" mirror possibilities

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

lou krajci wrote:
 >>From: "Bob May" <bobmay@nethere.com>
 >
 >
 >>The form for a Gregorian is a parabolic primary and an eliptical
 >
 > secondary....
 >
 > True, but let's expand our 'design thinking' a bit outside the box.
 >

 > Question for the group:  are there variants of the Gregorian (let's call
 > them 'compensated Gregorians') that use a non-paraboloidal main 
mirror, but
 > a concave secondary that can still correct for spherical aberration...so
 > that you have perfect on-axis images.  (Or does this end up with a design
 > with the focal plane in a strange place...like in front of the main 
mirror?)
 >

Yes.  Any of the forms described in:

	http://users.rcn.com/rflrs/twomirrors.htm

can apply to a Gregorian form as well as the Cassegrain.  (The
one with perfect on-axis images is the Classical.)

 > Thanks in advance.
 >
 > Tom Krajci
 > Albuquerque, New Mexico



-- 

Rick S.

http://users.rcn.com/rflrs


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