Glossary
T eph (Teph)
independent time argument of JPL ephemerides (Standish, A&A, 336, 381, 1998) that is, for practical purposes, the same as Barycentric Dynamical Time (TDB). TDB is related to Barycentric Coordinate Time (TCB) by
TDB = TCB - LB × (JDTCB - T0) × 86400 + TDB0, where T0 = 2443144.5003725, and
LB = 1.550519768 × 10-8 and TDB0 = -6.55 × 10-5 s
are defining constants. [IAU 2006 Resolution B3]Source: IERS Technical Note 36: Glossary (not accessible) [PDF, 244 KB] of the IERS Conventions (2010)
Temps-coordonnée barycentrique
Temps-coordonnée géocentrique
Terrestrial Dynamical Time (TDT)
time scale for apparent geocentric ephemerides defined by a 1979 IAU resolution and in 1991 was replaced by Terrestrial Time (TT).
Source: IERS Technical Note 36: Glossary (not accessible) [PDF, 244 KB] of the IERS Conventions (2010)
Original Source: IAU 2006 NFA Glossary
Terrestrial Ephemeris Origin
Acronym: TEO
The TEO is defined symmetrically with the CEO on the true terrestrial equator perpendicular to the CIP on the Earth.
Related terms:
Terrestrial Intermediate Origin (TIO)
origin of longitude in the Intermediate Terrestrial Reference System. It is the non-rotating origin in the ITRS that is recommended by the IAU 2000 Resolution B1.8, where it was designated Terrestrial Ephemeris Origin. The name Terrestrial Intermediate Origin was adopted by IAU 2006 Resolution B2. The TIO was originally set at the ITRF origin of longitude and throughout 1900-2100 stays within 0.1 mas of the ITRF zero meridian.
Source: IERS Technical Note 36: Glossary (not accessible) [PDF, 244 KB] of the IERS Conventions (2010)
Original Source: IAU 2006 NFA Glossary
Terrestrial Intermediate Reference System (TIRS)
a geocentric reference system defined by the intermediate equator of the CIP and the TIO (IAU 2006 Resolution B2). It is related to the ITRS by polar motion and s′ (see TIO locator). It is related to the Celestial Intermediate Reference System by a rotation of ERA around the CIP, which defines the common z-axis of the two systems. Since the acronym for this system is close to another acronym (namely ITRS), it is suggested that wherever possible the complete name be used.
Source: IERS Technical Note 36: Glossary (not accessible) [PDF, 244 KB] of the IERS Conventions (2010)
Original Source: IAU 2006 NFA Glossary
Terrestrial Reference Frame (TRF)
Realization of the Terrestrial Reference System (TRS), through the realization of its origin, orientation axes and scale, and their time evolution.
Source: IERS Technical Note 36: Glossary (not accessible) [PDF, 244 KB] of the IERS Conventions (2010)
Terrestrial Reference System (TRS)
A Terrestrial Reference System (TRS) is a spatial reference system corotating with the Earth in its diurnal motion in space.
Source: IERS Technical Note 36: Glossary (not accessible) [PDF, 244 KB] of the IERS Conventions (2010)
Terrestrial Time
Acronym: TT
TT is the coordinate time at the surface of the Earth.
TT is conventionally realized by TT = TAI + 32.184 s (although in fact TAI and TT are independent time scales, and different implementations of TT may differ by a few tens of microseconds.)
Related terms:
The Fifth Fundamental Catalogue
Acronym: FK5
The FK5 is a catalogue of positions and proper motions of fundamental stars.
Until the adoption of the International Celestial Reference Frame, the FK5 was the basis for all celestial positions.
Related terms:
Related links:
