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

[Reinhard Ilk <ilkr@ping.at>]

For those who understand some German there is an excellent documentation
on nearly any optical system used for astophotography: "Astrooptik" by
Uwe Laux, ed. Sterne und Weltraum, ISBN 3-87973-914-5. DEM 38.-, US$ 25.-

It is full of spot diagrams, sectional views, etc... and it helped me to a better understanding of advantages and drawbacks of the different types of telescopes.

Reinhard
ilkr@ping.at

Chuck Vaughn wrote:

> RCs do have astigmatism but I have not found
> it to be as bad as coma in
> an
> SCT. The OGS catalog shows spot diagrams for some typical scopes
> you
> might
> consider. The RC has the best off axis spot diagram. Also from
> their
> catalog,
> field curvature is comparable to a classical cassegrain or even
> slightly
> less.