> As Niels Foldager points out, _Dance of the Planets_ has the
> advantage of being able to numerically integrate objects. (I think
> it's the only popularly-available software to do this.) Were Guide
> able to do this, it could:
>
> (1) Show certain deep-space probes such as Voyagers 1 and 2, Galileo,
> Cassini, NEAR, etc.
>
> (2) Show heavily-perturbed objects such as P/Lexell, which was ejected
> from the solar system by Jupiter in 1770, and P/Shoemaker-Levy 9 (the
> one that collided with Jupiter in 1994).
>
> (3) Let you run experiments in which an object is added with a given
> position/velocity, and see where it goes.
>
> (1) and (2) can actually be more readily handled by pre-computed
> ephemerides, of the sort Guide now uses to show outer satellites of
> Jupiter, Saturn, Uranus, and Neptune. This yields greater accuracy
> and convenience, since it works by doing immense amounts of math _once_
> and storing the result. The third function would be rather pleasant to
> have, but I must admit that it is somewhat outside the realm of things
> I want to add to Guide!

OK, Bill. I'm happy that you are aware these possibilities.
So, who knows. May be you some day get borred... :-)

Best regards,

Niels Foldager
Copenhagen
Denmark