Royal Greenwich Observatory, UK
The Carlsberg Meridian Telescope on La Palma has carried out routine observations since 1984 of the positions of the outer planets, some of their satellites, and about 60 asteroids. A preliminary version of the Hipparcos catalogue has allowed us to refer these positions to the International Celestial Reference Frame (ICRF), thus eliminating systematic errors due to the reference frame.
The observations are compared with the latest JPL integration, DE403, which is also referred to the ICRF. A problem with the declination of Jupiter still remains.