Spiru Haret

Spiru Haret was a Romanian mathematician, astronomer and politician of Armenian descent. He made a fundamental contribution to the n-body problem in celestial mechanics by proving that using a third degree approximation for the disturbing forces implies instability of the major axes of the orbits and introducing the concept of secular perturbations in relation to this; (February 15 1851, Iaşi - 17 December 1912).