There were major perturbations of Chiron in about 586 and 718,
by Uranus and Saturn in order. This makes earlier orbits a
problem that a planetarium cannot solve, such as 14 BC and 2996 BC.
Four round asteriods, 7 planets and the moon and 
Jupiter in Opposition, lined up near the Sun in 2984 AD
http://www.bigberthathing.com/asteriods9.png