Time standard · TT
Terrestrial Time
The idealised time on the Earth's surface used as the time axis for astronomical events and geocentric ephemerides. It runs at the same rate as International Atomic Time but is offset ahead of it by a fixed 32.184 seconds, for continuity with the older ephemeris time.
Highlights
- ›TAI + 32.184 seconds
Bodies, frames & concepts
Across celestial mechanics
Knowledge connections
- Associated withThe J2000 Epoch
- Associated withInternational Atomic Time (TAI)
- Associated withThe J2000 Epoch
- Associated withBarycentric Dynamical Time
- Associated withJulian Date
Sources
The primary and reference sources this topic draws on.
- US Naval ObservatoryUnited States Naval Observatory
Precise time, almanac data, Sun/Moon rise-set, and phases.