ephemeris sidereal time历书恒星时
equation of ephemeris time历书时差
ephemeris qpparent sidereal time历书视恒星时
N（名词） time that is based on the orbit of the earth around the sun rather than the axial rotation of the earth, one ephemeris second being 556 925.9747 of the tropical year 1900. It was used from 1960 to 1983 as an astronomical timescale but has been replaced by terrestrial dynamical time and barycentric dynamic time 历书时