Re: [ATM] 6-pole

["Scott Ewart" <scotte@frontiernet.net>]

Rob,
	I built my 12.4" split ring using 6 poles.  It saves weight, it fits
better with my three-vane spider, and with my round "bucket" allowing a
rotating tube, there are no mounting point issues.  Looking in the front
end, "down the barrel", you can easily see what Richard refers to.  It's
much more striking than with 8 poles.  The tubes appear to "bend" inward as
they cross by the aperture, so you do need to account for that in your
design and be sure there's enough room in between the middle of the 6 poles.
	Alex also brings up an important point about a shroud.  Keep in mind
that at each end of the scope,  there are essentially only 3 points
supporting the shroud, allowing it to cross into the light path.  I solved
this by adding 6 strings (ultra-thin bungees) between the poles.  If you're
looking for quicker set-up time or simplicity, this may complicate things
too much for you.
	I've had mine a few years now and still haven't tired of any of the
complications.  I really love the scope.  It's up to you.

Scott Ewart



LDL> 6 poles completely define the position.
LDL> 8 poles over constrain the position.

Completely correct, hence the Hexapod. One disadvantage of 6 pole
though is that the poles impinge more toward the axis of the OTA, so a
larger starting diameter is required for the same clearance over the
optical path.

-- 

Best regards,
  Richard in the UK

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