Re: [ATM] Baffling a Gregorian and corrector plate fabrication.

["John Sherman" <atm@johnspics.com>]

Hi Doug,

>One thing I can't figure out is how to baffle such that stray 
>light can't get from the entrance aperture to the eyepiece. 

Here's a way that should work: http://www.johnspics.com/hi/Greg.gif (5kb). This is from an old issue of SciAm. Note that having the secondary at the focal point of the primary makes for a small secondary. However, every speck of dust will be in sharp focus, so it's best to move the secondary away from that position. Interesting how the secondary obstructs both the primary and the tertiary..

I've heard that making a parabola is easier and cheaper than making and collimating a corrector and a sphere, but I wouldn't know.

Good luck,

John





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