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 to tal 88 different comets were recorded in Chinese Ancient Records of Ce lestial Phenomena. According to those records, we reduced apparent pos itions and mean equatorial coordinates (epoch 2000.0) for all more tha n three times recorded comets. Taking into account the perturbations o f all nine planets and using the numerical method of N-body problem, t he orbits of correlative comets were calculated. For thirty different comets, new orbits are presented for the first time. (C) 1998 Elsevier Science Ltd. All rights reserved.