Re: ATM A cage as secondary holder

[Mike Burdo <mburdoo@azstarnet.com>]

Things that make us go hmmm.....:
Why not use steppers to control all the optical and mechanical adjustments?
Just think, push a button, and the scope collimates and boresites all by
itself.  Just a few lines of code....

ran@netgate.net wrote:

> In <199807210159.TAA13795@intergate.pvtnetworks.net>, on 07/20/98
>    at 07:59 PM, iss@pvtnetworks.net said:
>
> >Re the (re)movable secondary cages, one of the problems with building
> >accurate telescopes/mounts (in terms of tracking and finding things) in
> >amateur class systems is the need to have the telescope axes orthogonal
> >(ra/dec or alt/az), and have the optical axis also orthogonal to the
> >alt/dec axis. It's
> >not that hard to build the mount accurately and, once built
> >and aligned, it usually stays that way.
>
> I would guess that "usually" it doesn't:  i.e.,  that most mounts get
> moved frequently as they're hauled from observing site to site,  and back
> home to be "parked" between sessions.
>
> The axes will stayed aligned *with each other*,  but not with the rest of
> the universe.  So any control system needs provisions to compensate for
> that.  And the compensation factors need to be recalculated every time the
> mount is set up.
>
> Meanwhile,  unless you can rotate the tube (which is common,  I know), the
> error added by collimation movements is constant (for the observing
> session),  and can be compensated for by the same system that handles
> errors in polar alignment.  If you do rotate the tube,  a fairly quick
> recalibration should cancel out the new error constant.
>
> Ran
>
> --
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> ran@netgate.net
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