[ATM] Celestron 20" R-C telescope

[artbianconi@blast.net]

Why Two Truss Sections?

Of all the telescopes at the recent NEAF show, the one that was most 
memorable for me was the 18" prototype of Celestrons 20" R-C style 
telescope. It's not the conical mirror or size so much that intrigues 
me as was their choice to make the OTA out of two seperate truss 
systems.

Most every open truss telescope I've seen utilizes one set of tubes 
to secure the two mirror assemblies. For some reason, Celestron has a 
seperate, short lower cage for the primary and a seperate upper cage 
that is about 2-1/2 times longer than the primary one. Then joined 
them together. 

While two cages break down the truss tubes into something more 
compact and thus more transportable, that does not explain it for me. 
Two sets of truss tubes of the same length would be shorter and 
easier to move about than the tubes resulting from the cage ratio 
chosen.

I can see no manufacturing advantage either. In fact the design 
requires two additional machined rings of considerable size and twice 
as many tube attach points. It's also heavier because of the added 
components and fasteners.

With so many additional fasteners and components, ease of assembly 
seems hardly likely although I suspect that machines with this degree 
of sophistication do not get packed up and moved very often.

Superior mount rigidity could explain it but there are simpler ways 
of accomplishing that. 

Could they be trying to place a mounting point closer to the CG?

Can any one tell me what might have been the reasoning?

Thanks

Art Bianconi

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