Re: ATM Alt-alt telescope mounts and image rotation - long post

["Mel Bartels" <mbartels@efn.org>]

>>>
This sounds like the USAF satellite tracking setup they had near
here (Cloudcroft NM) about 30 years ago..it was a 48" Newt & the
guys there explained that it was a 3 axis mount, one of which
was set to near the orbital pole of the satellite, the other 2 used to
track the object.

I've been working on an altitude lead-screw drive mount design & this
may well work on an alt-alt-az also..if it actually gets rid of
field rotation it might be the *answer* to large amateur size
CCD imaging. Time to do some more homework..:)
<<<

Was it that large of scope?  Wow - that would be able to go pretty darn
faint on earth orbiting objects.  Though I suppose aperture and optics is
not the major cost of such a project...

I envision a dob with a small tilt motor on one side.  The tilt makes a
third axis and acts in conjunction with the other two motors to null the
field rotation.  It would have to be reset say every hour or so (BOE says 2
inches or +- 1inch of travel wrt the horizon) since its travel is limited.
That makes a 'universal' field derotator that can be applied to any
motorized dob or scope capable of being placed on a platform.

I am particularly intrigued by designs using three limited motions, ala a
fancy yet simplified equatorial table.  Tracy Wilson has gone down this path
and has one particular 3 axis design that will work nicely, if the
engineering problems can be overcome.

Mel Bartels