Moon Camera Values of ?T = ET? UT

Abstract

The ephemeris scale of time is based on the revolution of the Earth around the Sun. In 1956 the International Committee of Weights and Measures adopted a new definition of the second, the fundamental unit of time, in terms of ephemeris time. The second is the fraction 1/31556925· 9747 of the tropical year for 1900 January 0 at 12 hours, ephemeris time.