Re: [ATM] two mirror folded Newtonian

[Steve Beccue <lsteve@Beccue.com>]

I recall a neat Newtonian (possibly someone on this list) 
that used a relay lens to minimize the secondary size.  Couple
this with a secondary at a sharp angle and one might have
a very nicely folded Newt with a reasonably small secondary.

This idea allows the use of the existing primary.  The tube
is still long, but people can stand on the ground.  One more
secondary and a Nasmyth focus might be used!

Steve Beccue
steve@beccue.com

On Tue, 7 Mar 2006, Polaraligned wrote:

> 
> I used to be bent on doing a scope with a secondary "other than
> 45 degrees".  I did a lot of solid modeling in AutoCad and looked
> through the "virtual eyepiece" many times.  I believe my biggest

>  A much nicer design can be seen here:
> http://www.irony.com/Ed/astro/18inch/
> Unfortunately, the light baffles are not in place on this scope.  It would
> be interesting to see how Ed implements them.
> 
> I think folded designs can be well implemented and I think that f/8 is a
> great focal ratio to do it at.  I also think that the central obstruction 
> increase
> Scott
> 
> >
> > Peter wrote:
> >> Here is a scope you should check out. This is an 18" f/8 two mirror 
> >> folded
> >> design which is well baffled.
> >> http://www.johanneswilm.org/mike/telescope/
> >
> > Yes, this page has been pointed out before.
> >
> > While I admit that the eyepiece position is lower than a conventional
> > Newt., in my mind I can't call that telescope "well baffled",
> >
> > Mike L.
> >
> 
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