> 6) As for the LX200, what stops Guide from pumping data out faster!
> Guide could always allow the user to choose the update rate (oops,
> Markus posted this in his second message).
> The problem is the LX200 format is wasteful in serial bandwidth.

The other problem with the MEADE implementation is the nonacceptance of
new commands during the slew and sometimes the telescope stops totally
and has to be reset. Well designed TCSs don't show such behaviour.

> 7) I was going to point out that a PID is the simplest and not
> necessarily the best controller. At least it forms all or part
> of the inner loop. But as you said, estimating the future is
> an excellent approach. I was looking forward to doing this if
> Guide was to provide the info. I was also going to allow joystick
> inputs at the scope or outright manual motion to correct or
> completely take over the path estimation. If a satellite happened
> to be crossing your field of view, you'd slew after it and the TCS
> would quickly figure out an approximate path, but it might
> be hard to get it within a tiny CCD frame for long...

I wish you a lot of fun with control theory. But it's not really
necessary. The simple digital P-type control in Mel's TCS with a
sample rate of 18.2Hz is sufficient to track a satellite not nearby
the pole of the mount. Typical LEO satellites move with 1800"/s. That's
a pretty constant servo lag of 50" after the TCS catched the satellite.
It could be corrected by a constant forward term. The uncertainties
in the orbital elements and the mechanical pointing error of typical
amateur mounts are higher.

Markus Kempf