Toward consistency in the uses of ephemerides

The apparent coordinates in the printed material almanacs have inconsistencies concerning the reference frame. These inconsistencies produce secular errors of about 0 _. 001/century in the equatorial coordinates and periodic errors of about 0 _. 04 in the ecliptic coordinates. It is recommended that the calculation of apparent places of planets should be based on a consistent reference frame as well as on a consistent system of astronomical constants.