Page "Ephemeris time" Paragraph 12

Following this, an astronomical conference held in Paris in 1950 recommended " that in all cases where the mean solar second is unsatisfactory as a unit of time by reason of its variability, the unit adopted should be the sidereal year at 1900. 0, that the time reckoned in this unit be designated ephemeris time ", and gave Clemence's formula ( see Definition of ephemeris time ( 1952 )) for translating mean solar time to ephemeris time.