Re: [ATM] Unique New Equatorial Platform Design

[Dominic-Luc Webb <dlwebb@canit.se>]

On Sun, 11 Jun 2006, creator wrote:

> This is correct if you are speaking of a "Platonic ideal" circle.
> For an ATM to actually [achieve] a circle symmetrical enough to
> produce tracking smoothness measured in arc-seconds... THAT is
> more difficult. Also very difficult in practice is actually
> implementing an axis of rotation for that circle that is
> precisely perpendicular to its plane. :)

There are some aspects of this "new" design I find troubling. I
should first say that the poster (creator) has apparently done some
excellent construction, judging from his text and animation. If he
has achieved sub-arcsecond motion he at least deserves a pat on the
back. Many of us who have tried our own ideas have outright
failed this level of success.

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.

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

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.
When dealing with portable mounts, bad alignment, wind, ground
disturbances and atmospheric aberrations factor into the equation. On
an final note, I know of a couple professional astronomers who track
manually or use CCDs with feedback. In one case, no ATM would be
impressed with the homemade mount used.

Dominic-Luc Webb

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