Looking for Three Data of Halley's Comet Orbit

The semi-major axis of the orbit is about 17.9 astronomical unit, and the semi-minor axis of the orbit is about 0.6 astronomical unit. 1 astronomical unit =1490,000 kilometers, which is the average distance from the earth to the sun.

. tw/big 5/catalog/pu 3 1/20050523 12370 1/200507 18230950 . doc

In this paper, the orbital equation of Halley's comet is derived. However, the semi-major axis and semi-minor axis of the track are slightly different. Also, the orbit of comets is generally unstable and easily disturbed by the gravity of other celestial bodies.