ATM "Big" Dob Questions

[Peter Abrahams <telscope@europa.com>]

>>Where do you get this infamous "Kydex" stuff and why is it so good?  Can I
use black ABS instead?

When I went to get Kydex for a dew shield, flexible enough to curve into a
12 inch diameter cylinder, I was told that ABS was much tougher than Kydex,
at least in the form of a ~1/32 inch sheet.  I didn't experiment with the
two to confirm this.
The texture of the surface is also a consideration, I didn't want a glossy
surface, and the ABS was made with a textured surface.

>>Are aluminum truss poles better than steal?  Or does it matter much?

Roger, your lifestyle conversion is complete -- you're starting to spell
like an engineer.
There's a lot of types of aluminum.  Steel can be stronger than aluminum
that's made for house conduit, to extent that thinner wall steel tube
negates any weight advantage that aluminum has.  But with thin wall tubing
you might get more vibration problems.
I don't think there's a simple answer to this question, personally I'm not
sure it matters.
--Peter
_______________________________________
Peter Abrahams   telscope@europa.com   The history of the telescope & 
   the binocular:   http://www.europa.com/~telscope/binotele.htm