Re: [APML]: Thinking about a Ritchey-Chretien

[Wil Milan <wmilan@airdigital.com>]

Tom Krajci wrote:

> For larger aperture systems it's hard to beat an R-C design.  Every
> system. . .unless it is specifically designed for astrophotography. .
> .will have field curvature.  For an R-C a custom field
> flattener/corrector lens near the focal plane can help keep tighter
> star images over a larger piece of flat film.

That's true for scopes larger than amateur scopes. But for typical amateur optics (up to
12" - 16") and small film (35mm in particular) I've not seen anything which documents a
significant advantage of the R.C. + corrector vs. an equal-quality SCT + corrector or
even a good Newtonian + corrector.

When the scope and film size become much larger then the R-C does have some advantage,
but few of us shoot prime focus with film over 4" in size.

Wil M.
--
"When I consider your heavens, the work of your fingers,
the moon and the stars which You have set in place,
what is Man that you are mindful of him,
or the son of Man that you care for him?"  -- Psalm 8