On Feb 24, 2:04*am, Martin Brown
wrote:

If you want to do your own orbit determinations rather than derive the
equations from scratch then take a look at Project Plutos FindOrb.

And there's a link from there - didn't work, had to use Google - to
another program,

http://adams.dm.unipi.it/~orbmaint/orbfit/

of which source code in FORTRAN is available, so the mysteries of
orbit determination can be plumbed that way.

John Savard