Re: [ATM] Celestron 20" R-C telescope

["Scott Ewart" <scott.e@quicksurfer.com>]

    If you go to Chuck's link, and if you've never seen it before, you
should know that the pictures on that page just don't do his scope justice.
He's usually got way more stuff attached to and hanging from it.  He uses
three computers while imaging.  And the sounds it makes.  You just have to
be there.
    Have you seen the scope featured on the cover of the latest Amateur
Astronomy Magazine?  It's like that.  In fact, you might just have some
competition, Chuck.
    See you at TSP.

Scott Ewart


----- Original Message ----- 
From: "Chuck Shaw" <cshaw77072@ghg.net>
To: <atm@atmlist.net>
Sent: Tuesday, May 04, 2004 11:57 PM
Subject: Re: [ATM] Celestron 20" R-C telescope


Art,

I built my 14.5"f/5 newtonian years ago using two truss sections.  See a
picure at:  http://www.ghg.net/cshaw/truss.htm

The rationale was that because I was planning on carrying a lot of weight on
the sec cage (image plane de-rotator, finder, and CCD camera, etc. the
balance point was well up the OTA.  That would have resulted in a large
mirror box.  I tried "struts" to attach the alt sectors up higher with a
conventional box, but there was far too much viabration.

Because the balance point is not in the center of the OTA's length, the two
sets of trusses are not of equal length.

The two sets of trusses release with thumbscrews (no loose parts) and then
collapse like those folding chairs that slip into a thin sock like bag.

It is a design that has worked really well......  A side benefit is the wind
does not affect the scope as much as the long dobs that act like a
weathervane.

Chuck



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