From: "Rob" 
To: 
Reply-To: "Rob" 


Thanks for the info guys. I'm going to do it :)

I think I'll try a 6" one first. Not much of a lose if something goes wrong.

As far as the CCD's go... I checked out some of the pictures those guys had
posted ken. And while I give them kudos for making it work and taking some
very nice pictures considering the equipment. Comparing them to photo's
from the SBIG camaras....well theres just no comparison. I think a CCD is
probably something you don't want to skimp on if you want to take high
quality images.. I think I may try building one of those web cam
thingies...But I'll also save some and maybe try to by a used SBIG..

BTW why don't more people build Ritchies? Or have I just missed them all? hehe

Rob

----- Original Message -----
From: "Mel Bartels" 
To: 
Sent: Tuesday, February 25, 2003 11:36 PM Subject: Re: ATM Ritchey-Chretien
telescopes


>
> >>>
>  I know that the surface of a Ritchey-Chretien is hyperbolic
> instead of parabolic. What I'm curious about is, how much harder is a
> hyperbolic surface to grind and test compared to a parabolic surface?
> <<<
>
> It is NOT a single iota harder - what is more challenging or at least
> unusual is that you will have to adjust your testing to zero in on the
> hyperbolic figure.  Also realize that many of us touch up the final figure
> by playing with the secondary and primary playing with the figures until
the
> star test looks best.  I'd worry a lot more about figuring the convex
> secondary of a Cassegrain...
>
> Mel Bartels
>
>
>
>

--- BBBS/NT v4.00 MP