Hi folks,

I think Ned was asking about the situation for encoder-based
systems, when using Guide. In that case, the delay between
adding alignment stars does not matter. What _does_ matter, as
James suggested, is that the stars be separated in angular
distance.

For the LX-200 and Ultima 2000, which have built-in alignment
hardware, this is "the end of the story". For encoders as used
in Guide, you can also make use of more than just two alignment
stars. By doing so, you get somewhat improved alignment, _especially_
in the areas close to the alignment stars. All Guide has to do is to
look through its list of alignment stars and select two that are close
to the current area.

Theoretically, Meade and Celestron really ought to implement this
extremely simple and powerful technique in hardware. It's not especially
computationally or memory intensive, even for an embedded system.
Failing that, I may have to figure out a way to do it in software for
those scopes. That would consist of the following kludge: after
you've aligned your Meade/Celestron scope "normally", you could add
further alignment stars in Guide. That would let Guide think things
such as, "in the area of this star, the scope is pointing 2.3 arcminutes
south and 1.8 arcminutes east of the proper position... so when slewing
to targets in that area, aim 2.3 arcminutes north and 1.8 arcminutes west."

This is not a _good_ solution. The good solution would be to do it in
the scope's hardware. But we might settle for this...

-- Bill