To: atm{at}shore.net
From: Ian McKernan 
Reply-To: Ian McKernan 


Hi!  I've just put my 10" Telescope together and used a variation on a
"string scope" for the tube.

  Top and Bottom assembly are both square boxes.  A 20mm OD aluminium pole
sits in sockets at each corner.  Used 4 wires, each one running from a
corner of the mirror box, to an eyebolt in the corner of the top box
(adjacent to and just outside of the pole), and then back down the other
side (at 90 degrees) to the opposite corner of the mirror box.  Have
attached the wires by shackles through reinforced holes in the mirror box,
and tension comes from winding up wing-nuts that hold the eye-bolts.

Got the idea from a posting on this list a few weeks ago that talked about
X bracing a truss tube (which with all 4 wires on is what ive got).  I
think this was easier to build ( for a first timer anyway) than a
conventional truss.

Am taking it along to our local ATM group this week to star test the mirror
before coating, and will get some opinions there no doubt, but it seems to
work so far.  Will have to see how it stands up to real use over time.  If
i put the box on the ground and try to twist the top cage it will move, but
how often do you try and twist the top of a telescope??  I finally got the
thing collimated  last night and pointed at Jupiter, Moon etc.  If i gave
it a thump, it settled down again in about 4-5 seconds, and i think a lot
of this is from the mount (its a BIG box) not the tube assembly.

*********************************************************************
Ian McKernan
Plant Biology Technician

         c/o Murdoch University
         Division of Science and Engineering
         School of Biological Sciences and Biotechnology
         South St Murdoch  6150
         Western Australia
         tel: + 61-08-9360 2206
         fax: + 61-08-9360 6303

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