Published online by Cambridge University Press: 04 August 2017
The planetary and lunar ephemerides have their own inherent reference frame which is one of the key frames to be considered in the unification of the many present day frames, both celestial and terrestrial. The use of this frame requires an understanding of its own accuracies, both internal (i.e., relative) and external(e.g., w.r.t. the FK4 system or w.r.t. the dynamical equinox). Such accuracies are discussed in this paper. Also noted are the expected improvements in the future which will be obtained from newer data types.