Re: [APML] Well corrected Newtonian

["Tom & Lou Krajci" <krajcit@3lefties.com>]

From: <Aplanatic@aol.com>

> As some of you know, I have been pursuing the design of a large (16"
> aperture), well-corrected, wide-field astrograph for several years.  Has
it
> really been 4 years now?  Yikes.
>
> Anyway, to make a long story short, I've found several designs in the good
> old hyperbolic Newtonian family that use a 2-element corrector near the
focal
> plane....

I presume this is a flat field design?

This sounds somewhat similar to a Sky & Telescope article from about
1996...that was for an 8 inch hyperbolic newt with two element corrector.

> The basic design consists of a 16" hyperbolic primary at about f/6 with a
> deformation constant of about -1.45 (not too onerous to figure), a 5.5"
> diagonal and a 2-element corrector consisting of BK7 and F2 glasses....
>...Notably, the image
> characteristics are excellent inside an image square of the largest
> imaginable (to me) CCD camera out there, namely, the AP16.  Maybe
someday....
> <g>

I presume the color correction is also good for the near IR sensitivity of
CCD's?

Tom Krajci


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