JH> Sure would be nice to have a program calculating future JH> encounters. Jeff: Rob Matson's program "COLA" (for Collision Avoidance) does exactly that. Perhaps someone might obtain the archive COLA.ZIP and upload it to the SeeSat archive. The zip file is about 42k. There is a hitch if you don't have at least a 486-DX. COLA requires a math coprocessor. I have used it successfully with a 387 software emulator, however. Jim <jim.gorges@baremetl.com>