Re: [ATM] Collimating mechanisms

[Michael Lindner <mikell@optonline.net>]

On Sun August 14 2005 9:48 pm, Mel Bartels wrote:
> > But what controls the amount by which the angles change?
>
> The strings.   They stretch ever so slightly but still constrain the tip of
> the truss tube to an arc as it's lengthened/shortened

So, If I understand correctly, the strings cannot be in the same plane as the 
poles (or tilting does not decrease tension on the string). As per the 
following diagram we see 4 strings have increased tension, and 2 have 
decreased tension.

http://www.atmlist.net/contrib/mikell-at-optonline-dot-net/truss-collimation2.gif

There is still the matter of unwanted secondary tilt. What happens there?

Ya know, it looks like if we just change the relative tension on the strings 
rather than change the relative lengths of the poles, we could do this 
without the unwanted tilt...

Clear skies.
-- 
Michael Lindner
http://www.starastronomy.org *** http://home.att.net/~mikel
http://www.atmsite.org *** http://www.atmlist.net
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