from space.com
"Asteroid Ida has its own moon, Dactyl, on the right. Ida is about 35 miles (56 kilometers) across, compared to its moon, which is much smaller at a mile (1.6 kilometers) across."
there are aparently 2 asteriods known to have thier own moons... never thought about this before!
interesting
http://a52.g.akamaitech.net/f/52/827..._idas_moon.jpg