Noun: ephemeris time i'fe-mu-ris tIm
- (astronomy) a measure of time defined by Earth's orbital motion; terrestrial time is mean solar time corrected for the irregularities of the Earth's motions
"Astronomers use ephemeris time for precise orbital calculations";
- terrestrial time, TT, terrestrial dynamical time, TDT
Type of: time unit, unit of time
Encyclopedia: Ephemeris time