| EOP SERIES AVAILABE ON THIS WEB SITE | |||||||||
| EOP PC Combined series |
Reference system | Span | Sampling | Formal error | (x,y) | UT1-UTC ou UT1-TAI 3 |
UT-TE (TE: Ephemeris Time) |
Variation LOD | (dψ,dε) or (dX,dY)4 |
| IERS Reference Combined C04 (operationnal) |
ICRF-ITRF1 | 1962-current week | 1 day (fluctuations > 6-7 days) |
no | 1962- | 1962- | - | 1962- | 1962- |
| IERS Reference Combined C01 | ICRF-ITRF1 | 1846-last year | 0.05 year (~18.2 days) | yes | 1846- | 1962- | - | - | 1900- |
| IERS Reference Combined C02 | ICRF-ITRF1 | 1830-last year | 100 days | yes | 1830- | after 1958 | before 1958 | 1930- | - |
| Medium term (< 40 years) Individual series |
Reference system | Span | Sampling | Formal error | (x,y) | UT1-UTC | UT-TE (TE: Ephemeris Time) |
Variation LOD | (dψ,dε) or (dX,dY)4 |
| 11 GNSS series | see the series2 | ~1993-current month | 1 day, at 12 h | yes | often | always | - | often | |
| 20 VLBI series | ~1980-current month | variable : 5-7days | yes | often | always | - | rare | often | |
| 7 SLR series | 1983-current month | regular : 1 up to 4 days | yes | often | always | - | rare | - | |
| 2 DORIS series | ~1992-current month | 1 day with exception | yes | always | always | - | often | - | |
| Long term (> 40 years) Individual series |
Reference system | Span | Sampling | Formal error | (x,y) | UT1-UTC ou UT1-TAI 3 |
UT-TE (TE: Ephemeris Time) |
Variation LOD | (dψ,dε) or (dX,dY)4 |
| LOD/UT1 from ancient eclipses | - | 2000BC-2016 | 1 year | yes | - | - | 2000BC-2016/td> | 2000BC-2016 | - |
| Mean pole | - | 1900-last year | 1 year | yes | - | - | - | - | - |
| 2 optical series | - | 1900.0-1992.0 | variable : 2-10 days | yes | - | 1956-1992 | - | 1900-1992 | 1900-1992 |
| LOD | - | 1832-1997 | 1 year | yes | - | - | - | 1832-1997 | - |
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1 EOP adjust the transformation from the International Celestial Reference Frame to the International Terrestrial Reference frame.
2For the "individual" series the reference frame are not necessarily the international frames. The associated frames can present rotation with respect to the international frames up to a few milliarcseconds. See consistency. 3In order to compute UT1-TAI from UT1-UTC or inversely, we provide the offsets TAI-UTC and the associated FORTRAN software. UT1-TAI series can be also derived from UT1-UTC series by using this interactive tool. 4The celestial pole offsets (dψ ,dε) are referred to the precession-nutation model UAI 1980, but the offsets (dX,dY) are referred to the new conventional model UAI 2000. Presently all the available celestial pole offsets time series are provided under the form (dψ ,dε)/ IAU 1980 and (dX,dY) / UAI 2000. In the future (2016-2020) the series (dψ ,dε) / UAI 1980 will disappear for the exclusive benefit of (dX,dY) / UAI 2000. The transition from (dψ ,dε) / UAI 1980 to (dX,dY) / UAI 2000 or inversely can be achieved numerically by the software proposed by the EOP-PC. Some users may prefer the parameter (dψ ,dε) / IAU 2000, and then can use the approximation (error below 1 microarcsecond over 1980-2020):
dψ sin ε0= dX or the accurate relation, written in the chapter 5 of the IERS 2010 conventions, of which the programmation is proposed here (see uai package 2000). |