Re: [ATM] Equatorial Platform for small dob

[Bill Prewitt <bprewitt@neo.rr.com>]

I built a Shaw equatorial platform (cylindrical bearing) for 41 degrees 
latitude. It worked fine with a 12" dob for visual but not photographic 
tracking. Mine is here:
    http://www.astrocaver.com

Chuck's design plans are archived at ATMSITE
    http://www.atmsite.org/contrib/Shaw/platform/
Just Google "equatorial platform" for many more pages of links.

With the cylindrical bearing design, the N bearing section becomes 
smaller as you build for higher latitude, so the platform needs to be 
taller to achieve the same duration of tracking, lest the corners touch 
the ground. It also has a narrow stance and is easier to tip at the 
extreme ends of tracking.  41 degrees worked well - any experience out 
there at higher latitude ?
          Bill Prewitt



Bruce MacDonald wrote:
> 
> So...
> Two questions:
> 1.  What is the practical latitude limit for such an arrangement,
> 2.  Does anyone know of published plans or design information
> available that would enable me to design and build my own?
> 
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