New reductions of orbits based upon Chinese ancient cometary records

From 146 B.C. to 1760 A.D., 363 sets of cometary observations for a total 88 different comets were recorded in Chinese Ancient Records of Celestial Phenomena. According to those records, we reduced apparent positions and mean equatorial coordinates (epoch 2000.0) for all more than three times recorded comets. Taking into account the perturbations of all nine planets and using the numerical method of N-body problem, the orbits of correlative comets were calculated. For thirty different comets, new orbits are presented for the first time.