Re: ATM stiffness requirements for truss tubes

[VVHITEFIRE@aol.com]

In a message dated 12/31/98 10:37:35 AM Central Standard Time,
Douglas.S.Angle@can.dupont.com writes:

<< 
 2) The tubes are going to be about 6 feet long, making them inconvenient to
 transport.  I would like to make them in sections, preferably telescoping.
 This will then give additional flexure at the joint.  Will this be a
 problem?  Any elegant (ie. lightweight) solutions?
  >>
While knowing a little about industrial physics, I can say that telescoping
truss tubes will give you collimation nightmares as long as you use them.  Go
for larger mirror boxes and shorter truss tubes, and use a triangular pattern
in the truss tubes.  The extra weight will be welcome when it comes time to
set it up, especially if you're using a long tube.  Copy Palomar, but save
yourself the price of a large dose of Ibuprofen every observation night, and
use monolithic tubes.

Kevin