The Effect of Equinox Correction on the Determination of the Ephemeris Time

Spencer Jones' Rediscussion of the occulation is approximately referred to the system of Newcomb's Fundamental Catalogue. Therefore, if we compute the correction AT0 based on the Improved Ephemeris and the FK3 star system, 27.32 Aa'0 cos o--1.21. should be added to AT0, in order to obtain AT, which is consistent with the definition given from the Sun's mean longitude, where Aa'0 Newcomb-FK3. If we use Robertson's Catalogue, 1.34 should be added to it, instead of 1.21.