Hi Philippe,

I rendered those images, and similar ones for the Saturnian and
Uranian systems (see http://www.projectpluto.com/ssats.htm and
http://www.projectpluto.com/usats.htm ) with a little program I
wrote for the purpose. It is heavily user-abusive, because I wasn't
thinking along the lines of distributing it; and if you attempt to
display more than about a dozen objects, the result is too
"spaghetti-like" to be very useful.

I went to the effort of doing it because I thought it possible that
I could see some pattern to the orbits of these objects. (The
pattern for Jupiter is very clear: there is one inner group of
prograde objects, all with similar inclinations and periods,
and one group of outer objects, again with similar inclinations
and periods. The groups for Saturn and Uranus are less
obvious, but are there. None of this is at all obvious from
the orbit graphs; you have to look at the tables of orbital
elements to see what is going on.)

So I didn't learn anything very useful from the program, but
got some "pretty pictures" of the orbits to show on the Web
site.

If you can find another program to show orbits (I don't know
of one, but surely _someone_ must have done this!), I'd
advise using it. Otherwise, let me know, and I'll post mine,
and you can give it a try... I only suggest you look elsewhere
because mine was a quick, dirty, not-very-good effort.

-- Bill