Re: [ATM] squaring truss tubes and collimation

["john sherman" <atm@mail.johnspics.com>]

Hi Jay,

>Here's something I've never seen discussed:  the importance of 
>making sure your truss tube telescope components are square.

That is something Steven Overholt taught me, many years ago. I like your idea of cutting sticks, I've always used a tape measure across the diagonals between the UTA and mirror box. 

Another trick to making your truss assembly strong and repeatable in setup is to make the truss out of triangles. My 22" uses four triangles instead of 8 separate poles, in a manner similar to StarMaster scopes. Each triangle is marked and the scope goes together the same each time, keeping the UTA centered over the mirror box. In fact I had the whole thing built and setup and pointing straight up, except that I used clamps to position the UTA on the triangles. Then I carefully measured and adjusted the clamps and measured over and over. When the UTA was centered I then drilled the holes for the mounting bolts. 

Since the triangles are stronger than the clamp blocks, once the poles are on I can tip the scope down, then install the UTA while standing on the ground. It's scary watching these guys at the top of their ladders leaning out over their mirrors and trying to install the UTA onto 8 loose poles at the same time. 

You probably won't be able to do this with your scope, with all the different length poles, but perhaps something can be figured out. 


John









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