Re: [ATM] field curvature

[Richard <cnc@cncservo.co.uk>]

Hi Jonathan,

Friday, April 22, 2005, 3:33:21 PM, you wrote:

JL> Hello, while optimizing my RC I was wondering what
JL> field curvature a 2" eyepiece is confortable with? My
JL> eyepiece is a Meade Super Plossl 56mm.

The way to decide is to force the image plane curvature to
Infinity in your optics software and then look at the spot
diagram, particularly at the extreme of the field that the
eyepiece will se and decide from it's size if it will bother you
or not.

I have my 16" corrected RC optimised for a 50mm field diameter
and it is diffraction limited by a good margin. You are welcome
to the prescription but my secondary diameter is 160mm. That
could be made smaller for your diagonal mirror configuration but
I doubt a good solution exists with a 50mm field and a small
secondary. The problem for the corrector is that as the back
focal length from secondary to focal plane gets smaller, then
the cone gets faster and gives the corrector a much bigger job
to do.

-- 

Best regards,
 Richard



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