IERS-OP CURL / WEB SERVICE

Theses 3 services below display data on a webpage and you can retrieve these datas in your script or program with the command "curl". You will need this command installed on your computer

Traditionnal webservice has been abandonned.

1- Leap second

This page gives the current value of UT1-UTC, the date of the last leap second and the date of the next leap second. If no leap second is scheduled, then it ouputs "Not scheduled". This page relies on the information of the last Bulletin C and the current date.

- Address of the page :

http://hpiers.obspm.fr/eop-pc/webservice/CURL/leapSecond.php

Input : none

Output : UT1_TAI (UT1- TAI)| Last_leap_second | Next_leap_second

- Exemple of shell command in order to get these data in your script or program :

curl "http://hpiers.obspm.fr/eop-pc/webservice/CURL/leapSecond.php"

2- Earth orientation parameters from civil date (combined series C04 - click here for description)

- Address of the page :

http://hpiers.obspm.fr/eop-pc/webservice/CURL/date_to_EOP.php?year=2000&month=12&day=25

Input variables : year (YYYY), month (MM), day (DD)

Ouput variables : MJD, x("), y" , UT1UTC(s), LOD(s), dX("), dY("), xerr("),yerr("), UT1UTCerr("), LODerr(s), dXerr("), dYerr(")

- Exemple of shell command in order to get these data in your script or program :

curl "http://hpiers.obspm.fr/eop-pc/webservice/CURL/date_to_EOP.php?year=2000&month=12&day=31"

3- Earth Orientation Matrix at a given instant - see also

- Address of the page :

http://hpiers.obspm.fr/eop-pc/webservice/CURL/date_to_EOP_matrix.php?year=2000&month=12&day=25&hour=12&minute=30&second=15&pm=1&ut=0&nut=1&tides=0

Input variables : year(YYYY), month(1-12), day(1-31), hour(0-23), minute(0-59), second(0-59), pm (0-1), ut (0-1), nut (0-1), tides (0-1)

Ouput variables : MJD, x("), y(") , UT1UTC(s), LOD(s), dX("), dY("), xerr("),yerr("), UT1UTCerr("), LODerr(s), dXerr("), dYerr (")

- Exemple of shell command in order to get these data in your script or program :

curl "http://hpiers.obspm.fr/eop-pc/webservice/CURL/date_to_EOP_matrix.php?year=2000&month=12&day=25&hour=12&minute=30&second=15&pm=1&ut=0&nut=1&tides=0"

Transformation coordinate M from the international terrestrial reference system (ITRF) to the international celestial reference frame (ICRF) :
Celestial coordinates ( X Y Z) = M x Terrestrial coordinates ( x y z )
We use the FORTRAN CODE of the VLBI analysis Software GLORIA developped by Anne-Marie Gontier (Paris Observatory), and compatible with the IAU 2000 resolutions

from 1962 to the current week the matrix can include the whole EOP set of the IERS combined series C04 (daily step, 0hUTC, time resolution for such EOP fluctuations is about 6 days), as well as diurnal and semi-diurnal effects produced by ocean tides, which amount about 0.001". Accuracy is 0.0001", corresponding to 5 10^-10 rad. In turn the time resolution of the matrix can reach approximatively 6 hours. Bewteen two dates at 0hUTC the EOP are interpolated according to a cubic spline.

from the current week to 6 months after the matrix is computed from the prediction of the polar motion and UT1-UTC.

outside the range [1962, current week+ 6 months prediction] the rotation matrix is restricted to the diurnal rotation and the precession-nutation model IAU 2000.

The last digit (12) of the matrix element corresponds to the pico radian level. Corresponding time resolution for the matrix variation is 14 nano seconds.

Components of the instantaneous rotation vector are deduced from the orientation matrix and its time derivative.