Note on variability of the time Standard due to the relativistic effect

By using the Schwarzschild fundamental line element, the difference between the coordinate time and the proper time is derived for the planetary motions. The amount is shown for the earth: dt/ds= 1+1.48X10-8+3.3X10-i0 cosw, where t is the coordinate time, S is the proper time, and w is the true anomaly. The identification of the co- ordinate time as Ephemeris Time and that of the proper time as Atomic Time are discussed, although these are open for experiments.