Carlsberg Positions of Planets Compared with JPL DE403

Abstract

A b s t r a c t . The Carlsberg meridian telescope has made nearly 20 000 observations of outer Solar System objects since it began operation in 1984. A preliminary version of the Hipparcos catalogue has been used to refer the positions to the International Celestial Reference Frame (ICRF). The observed positions of the major planets are compared with JPL DE403 which is also referred to the ICRF. The agreement with DE403 is good, except for the declination of Jupiter where there is a systematic difference reaching 0"15 in 1995. The cause of this discrepancy is being investigated at JPL with recent VLBI observations of Galileo.