From: Dale Eason 
To: Dale Eason , atm{at}shore.net
Reply-To: Dale Eason 


Oh I'm meant reducing the upper and lower truss diamters.
Sorry

-+- Dale Eason  wrote:
>
> I have been giving thought to how I will build the
> truss for my 16" f5.  I already have an 8" f8 truss
> scope and think I understand it pretty well.  I
> designed it using Grape finite analysis about 5
> years
> ago.  It has lived up to the Grape simulation.  I am
> trying to make the 16 incher an ultra light.
> Keeping
> the truss tube weight down is important.
>
> It seems to me that in the standard 8 tube truss for
> a
> Dobsonian alti-azimuth mount that only the left and
> right sides need to be very strong as they carry the
> weight of the OTA load against gravity.  The left
> and
> right pair only help to keep the OTA from rotating
> and
> aligned left and right  to the mirror when the OTA
> is
> pushed by a sideways force.  Usually that side force
> is much smaller than the altitude force.  Thus I
> think
> that the upper and lower trusses can be made out of
> much smaller diameter tubing saving a lot of weight.
>
> I know that some have gone to a 6 tube truss but I'm
> not really ready to do that yet because I can't
> figure
> out how to attach it to the square mirror box.  I
> guess I should look closer at Mel's pictures.
>
> Anybody have any thought about reducing the left and
> right truss diameters?
>
> Dale Eason
>
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