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General Information

IERS Conventions 2010

The Conventions contains detailed information on definitions and models used to determine Earth Orientation.

Refer here for the latest updates to the Conventions.

IERS Conventions 2003  

Please note: This links to the 2003 IERS Conventions.

IERS Conventions 1996   

Please note: This links to the 1996 IERS Conventions.

Units commonly used for Earth Orientation

Date and Time Definitions

Interpolating IERS Earth Orientation data

This is the IERS Gazette #13 (ASCII).  Please note that the recommended routine does not

interpolate UT1-UTC properly around a leap second.

Data series used in IERS Bulletin A

These are the raw observations which contribute to IERS Bulletin A.

Systematic Corrections

Systematic corrections that are applied to Combination procedure.

Changes to Bulletin A (archive)

Archive of changes to Bulletin A since 2007.

Past issues of Bulletin A

Past issues of Bulletin A are archived at Crustal Dynamics Data Information Center (CDDIS).

Plots of Past Earth Orientation

Plots of past EOP variations (including comparisons with atmospheric excitation).

Bulletin B

Reports the "final" Earth Orientation values.

Bulletin C

Leap Second Announcements.

Bulletin D

Announcements of DUT1 (UT1-UTC).

USNO Master Clock Time
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