Re: [ATM] Unique New Equatorial Platform Design

[creator <creator@subarcsec.com>]

Greetings Dominic-Luc and Friends!

Here are some more specific responses to Dominic-Luc Webb:

 > One of the strengths of such designs is their potential to operate
 > without electricity. For those of us who operate in places where we
 > are not permitted to have electricity, such designs are tempting.

This is true. One variant of the hydraulic mechanism I have contemplated
is a cylinder with a check-valve arrangement. As the platform descends,
fluid is metered from the bottom to the top of the cylinder. When it is
time to reset, simply lift the corner of the platform and allow the fluid
to pass through the check valve in the piston, returning to the lower
portion of the cylinder.

 > I specifically recall discussions earlier about the challenge of
 > building similar mounts. I also do not see originality here, so much
 > as what looks like sound construction. It may be this feature
 > that is novel and should be exploited.

The most significant novelty is in the polar axis design, which I
will elaborate on in another post; it is, however, pretty extensively
described on the web site. It is NOT a "barn-door" hinge. It is also
very well suited to carrying the weight of VERY large instruments.

 > We have yet to see many details of the complete construction.
 > I look forward to this.

Please advise as to specific important details that in your estimation
are missing, and I will post photos at http://subarcsec.com and will
also comment on construction details.

 > One advantage I can speak for after some testing of a related concept,
 > was that hydraulic and pneumatic systems do not have the vibration
 > inherent to motors. The motorized designs I have built all required
 > very deliberate and sometimes extensive work to dampen vibrations.

Also very true. One other comment; silent in operation. :) You can be
playing your Mozart or Bach or whatever without any distracting motor
sounds. In the prototype, there is a pleasant trickling water sound. :)

 > As for reaching sub-arcsec tracking, many of us have achieved this
 > very nicely with most of the common mounting configs. Various methods
 > of correction during the tracking can even deal with atmospheric
 > effects, etc, that even a "perfect" equatorial will not compensate for.

I understand this; my goal is [elimination] of Periodic Error - as well as
the elimination of what I call "Periodic Marriage Error" - Example: "But
Honey, I absolutely, positively NEED that $12,000 AP mount!"... :)

 > When dealing with portable mounts, bad alignment, wind, ground
 > disturbances and atmospheric aberrations factor into the equation.

My implementation has seemed pretty solid and stable, even in the face
of the dust bowl that was RTMC this year. :) Not sure about ground
disturbances... do you mean earthquakes? :) As far as bad alignment goes,
the widely spaced geometry and polar axis concept of my design make it
far easier to achieve dead-on alignment than typical designs.

Thanks for your thoughtful comments!

Regards,

-Dann
================================================================
Dann McCreary http://flyinghouse.com    creator-at-subarcsec.com
SubArcSecond Tracking Accuracy!  --   Visit http://subarcsec.com
Read The Bills Act http://www.downsizedc.org/read_the_laws.shtml
================================================================
"The heavens are telling of the glory of God;  and their expanse
  is declaring the work of His hands"  -     Psalm 19:1    (NASB)
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