AppendixTIMEKEEPING ORGANISATIONS

International organisationsSeveral organisations share the responsibility for the world timekeep-ing system. They all have websites, some of which contain extensiveresources on timekeeping.

Bureau International des Poids et Mesures (BIPM)BIPM is custodian of all the worlds units of measurement, and since1988 has been responsible for the formation of the TAI and UTC timescales. The Bureaus monthly Circular T, which publishes correctionsto UTC disseminated by the national timing centres, can be downloadedfrom the website.Address: Time Section, BIPM, Pavillon de Breteuil, F-92312 Se`vres,France.Website: http://www.bipm.fr

International Earth Rotation Service (IERS)Created in 1988 by the International Astronomical Union (IAU) and In-ternational Union of Geodesy and Geophysics (IUGG), the IERS main-tains terrestrial and celestial reference frames and monitors the Earthsrotation. It is responsible for deciding when a leap second is required tomaintain UTC close to UT1. The website gives access to a vast amountof data on Earth orientation, including the various Bulletins.Address: International Earth Rotation Service, 61 avenue delObservatoire, F-75014 Paris, France.Website: http://hpiers.obspm.fr

183

184 TIMEKEEPING ORGANISATIONS

International Astronomical Union (IAU)The IAU was founded in 1919 to promote and coordinate worldwide co-operation in astronomy. It no longer plays a central role in timekeepingbut still maintains a Time Commission which supervises the work of theIERS.

Address: International Astronomical Union, 98bis Bd. Arago, F-75014Paris, France.Website: http://www.iau.org

International Telecommunication Union (ITU)The ITU is an international organisation within which governments andthe private sector coordinate global telecom networks and services. It isresponsible for the international agreements that define UTC in terms ofTAI.

Address: International Telecommunication Union, Place des Nations,CH-1211 Geneva 20, Switzerland.Website: http://www.itu.int

National organisationsMany countries have national timing laboratories: the following are justa few that have been mentioned in this book, including all those operat-ing primary frequency standards which contribute to TAI.

Communications Research Laboratory (CRL), JapanFounded as the Radio Research Laboratory in 1952 but with roots reach-ing back to 1896, CRL operates a new optically pumped primary stan-dard, CRL-O1, based on the design of NIST-7 and controls the timesignals emitted from radio stations JG2AS and JJY.

Address: Communications Research Laboratory, 4-2-1, Nukuikita-machi, Koganei-shi, Tokyo 184, Japan.Website: http://www.crl.go.jp

National organisations 185

Institute of Metrology for Time and Space (IMVP), RussiaIMVP operates the caesium beam standard MCsR-102 and a series oftime and frequency radio stations including RBU and RWM.

Address: IMVP, GP VNIIFTRI, Mendeleevo, Moscow Region,141570, Russia.

Institute for National Measurement Standards (INMS), CanadaThe INMS, a laboratory of the National Research Council of Canada,operates two caesium beam standards known as CsVI-A and CsVI-C. Italso controls the radio station CHU.

Address: Institute for National Measurement Standards, Montreal Road,Building M-36, Ottawa, Canada, K1A 0R6.Website: http://www.nrc.ca/inms/inmse.html

Laboratoire Primaire du Temps et des Frequences (LPTF), FranceOne of the five national laboratories of the Bureau National deMetrologie (BNM), LPTF is responsible for the French time andfrequency standards. It operates the worlds first caesium fountain,LPTF-FO1, which is the most accurate primary standard to date.

Address: BNM-LPTF, Observatoire de Paris, 61 avenue de lObservatoire,F-75014 Paris, France.Website: http://opdaf1.obspm.fr

National Institute of Standards and Technology (NIST), USAFounded as the National Bureau of Standards (NBS) in 1901, NISThosts the primary standards NIST-7 and NIST-F1 and controls radiostations WWV, WWVH and WWVB. Much of the pioneering researchinto atomic clocks was carried out at NBS and the first atomic clock,based on a transition in ammonia, was constructed there in 1948.

Address: National Institute of Standards and Technology, 325 Broadway,Boulder, CO 80303-3328, USA.Website: http://www.bldrdoc.gov/timefreq

186 TIMEKEEPING ORGANISATIONS

National Physical Laboratory (NPL), UKNPL is the UK national standards laboratory, where the worlds firstoperational caesium clock was constructed in 1955. It controls the radiostation MSF.

Address: National Physical Laboratory, Teddington, Middlesex TW110LW, UK.Website: http://www.npl.co.uk

National Research Laboratory of Metrology (NRLM), JapanNow part of the Agency of Industrial Science and Technology, NRLMhas been the national standards laboratory of Japan since 1903. It oper-ates NRLM-4, an optically pumped caesium beam standard.

Address: National Research Laboratory of Metrology, 1-1-4, Umezono,Tsukuba, Ibaraki 305-8563, Japan.Website: http://www.aist.go.jp/NRLM

Physikalisch-Technische Bundesanstalt (PTB), GermanyPTB is Germanys national standards laboratory. In the 1930s PTBscientists were among the first to discover seasonal changes in the Earthsrotation and they now operate the worlds most reliable primary fre-quency standards. PTB also runs radio station DCF-77.

Address: Physikalisch-Technische Bundesanstalt, Postfach 3345, D-38023 Braunschweig, Germany.Website: http://www.ptb.de

United States Naval Observatory (USNO), USAUSNO plays a leading role in both astronomical and atomic timekeeping,and operates the worlds largest ensemble of atomic clocks. In the 1950sUSNO astronomers collaborated with NPL scientists to calibrate theatomic second in terms of Ephemeris Time.

Address: United States Naval Observatory, 3450 Massachusetts AvenueNW, Washington, DC 20392-5420, USA.Website: http://tycho.usno.navy.mil

Other websites about timekeeping 187

Other websites about timekeepingScience Museum (http://www.nmsi.ac.uk/collections//exhiblets/atomclock/start.htm)Properly known as the National Museum of Science and Industry, theLondon Science Museum is the final resting place of the first operationalcaesium clock designed by Essen and Parry at NPL.

Royal Observatory Greenwich (http://www.rog.nmm.ac.uk)The Royal Greenwich Observatory is no more but its legacy is preservedat the old Royal Observatory in Greenwich which is part of the NationalMaritime Museum, along with much of interest to do with timekeeping.

Long Now Foundation (http://www.longnow.org)Information about the project to build a monumental clock to last 10 000years.

GPS (http://www.laafb.af.mil/SMC/CZ/homepage)Control centre for the US satellite navigation system.

GLONASS (http://mx.iki.rssi.ru/SFCSIC//english.html)Control centre for the Russian satellite navigation system.

Time around the world (http://www.timeanddate.com andhttp://www.worldtime.com)Two sites which can tell you the local time for any place in the world.

Horology (http://www.horology.com)A guide to many web-based resources about timekeeping.