The International Time Bureau (french: Bureau International de l'Heure, abbreviated BIH), seated at the

Paris Observatory The Paris Observatory (french: Observatoire de Paris ), a research institution of the Paris Sciences et Lettres University, is the foremost astronomical observatory of France, and one of the largest astronomical centers in the world. Its histor ...

, was the international bureau responsible for combining different measurements of

Universal Time Universal Time (UT or UT1) is a time standard based on Earth's rotation. While originally it was mean solar time at 0° longitude, precise measurements of the Sun are difficult. Therefore, UT1 is computed from a measure of the Earth's angle wit ...

. The bureau also played an important role in the research of

time keeping Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...

and related fields:

Earth rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space. Earth rotates eastward, in prograde motion. As viewed from the northern polar star Polar ...

reference frames In physics and astronomy, a frame of reference (or reference frame) is an abstract coordinate system whose origin, orientation, and scale are specified by a set of reference points― geometric points whose position is identified both mathe ...

, and

atomic time International Atomic Time (abbreviated TAI, from its French name ) is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid. TAI is a weighted average of the time kept by over 450 atomic ...

. In 1987 the responsibilities of the bureau were taken over by the

International Bureau of Weights and Measures The International Bureau of Weights and Measures (french: Bureau international des poids et mesures, BIPM) is an intergovernmental organisation, through which its 59 member-states act together on measurement standards in four areas: chemistry, ...

(BIPM) and the International Earth Rotation and Reference Systems Service (IERS).

History

The creation of the BIH was decided upon during the 1912 ''Conférence internationale de l'heure radiotélégraphique''. The following year an attempt was made to regulate the international status of the bureau through the creation of an

international convention International law (also known as public international law and the law of nations) is the set of rules, norms, and standards generally recognized as binding between states. It establishes normative guidelines and a common conceptual framework for ...

. However, the convention wasn't ratified by its member countries due to the outbreak of

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

. In 1919, after the war, it was decided to make the bureau the executive body of the ''International Commission of Time'', one of the commissions of the then newly founded

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

(IAU). From 1956 until 1987 the BIH was part of the Federation of Astronomical and Geophysical Data Analysis Services (FAGS). In 1987 the bureau's tasks of combining different measurements of

were taken over by the

BIPM The International Bureau of Weights and Measures (french: Bureau international des poids et mesures, BIPM) is an intergovernmental organisation, through which its 59 member-states act together on measurement standards in four areas: chemistry, ...

. Its tasks related to the correction of time with respect to the

celestial Celestial may refer to: Science * Objects or events seen in the sky and the following astronomical terms: ** Astronomical object, a naturally occurring physical entity, association, or structure that exists in the observable universe ** Celes ...

reference frame In physics and astronomy, a frame of reference (or reference frame) is an abstract coordinate system whose origin (mathematics), origin, orientation (geometry), orientation, and scale (geometry), scale are specified by a set of reference point ...

and the

earth's rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own Rotation around a fixed axis, axis, as well as changes in the orientation (geometry), orientation of the rotation axis in space. Earth rotates eastward, in retrograd ...

were taken over by the IERS.

References

Standards organizations in France Timekeeping Paris Observatory {{int-org-stub