leapseconds revision 192886
1178828Sdfr# <pre> 2178828Sdfr# @(#)leapseconds 8.8 3178828Sdfr# This file is in the public domain, so clarified as of 4225778Sstas# 2009-05-17 by Arthur David Olson. 5178828Sdfr 6233294Sstas# Allowance for leapseconds added to each timezone file. 7233294Sstas 8178828Sdfr# The International Earth Rotation Service periodically uses leap seconds 9233294Sstas# to keep UTC to within 0.9 s of UT1 10233294Sstas# (which measures the true angular orientation of the earth in space); see 11233294Sstas# Terry J Quinn, The BIPM and the accurate measure of time, 12233294Sstas# Proc IEEE 79, 7 (July 1991), 894-905. 13233294Sstas# There were no leap seconds before 1972, because the official mechanism 14233294Sstas# accounting for the discrepancy between atomic time and the earth's rotation 15233294Sstas# did not exist until the early 1970s. 16233294Sstas 17233294Sstas# The correction (+ or -) is made at the given time, so lines 18233294Sstas# will typically look like: 19233294Sstas# Leap YEAR MON DAY 23:59:60 + R/S 20233294Sstas# or 21233294Sstas# Leap YEAR MON DAY 23:59:59 - R/S 22233294Sstas 23233294Sstas# If the leapsecond is Rolling (R) the given time is local time 24233294Sstas# If the leapsecond is Stationary (S) the given time is UTC 25233294Sstas 26233294Sstas# Leap YEAR MONTH DAY HH:MM:SS CORR R/S 27233294SstasLeap 1972 Jun 30 23:59:60 + S 28233294SstasLeap 1972 Dec 31 23:59:60 + S 29233294SstasLeap 1973 Dec 31 23:59:60 + S 30233294SstasLeap 1974 Dec 31 23:59:60 + S 31233294SstasLeap 1975 Dec 31 23:59:60 + S 32233294SstasLeap 1976 Dec 31 23:59:60 + S 33233294SstasLeap 1977 Dec 31 23:59:60 + S 34233294SstasLeap 1978 Dec 31 23:59:60 + S 35233294SstasLeap 1979 Dec 31 23:59:60 + S 36233294SstasLeap 1981 Jun 30 23:59:60 + S 37233294SstasLeap 1982 Jun 30 23:59:60 + S 38233294SstasLeap 1983 Jun 30 23:59:60 + S 39233294SstasLeap 1985 Jun 30 23:59:60 + S 40233294SstasLeap 1987 Dec 31 23:59:60 + S 41233294SstasLeap 1989 Dec 31 23:59:60 + S 42233294SstasLeap 1990 Dec 31 23:59:60 + S 43233294SstasLeap 1992 Jun 30 23:59:60 + S 44233294SstasLeap 1993 Jun 30 23:59:60 + S 45233294SstasLeap 1994 Jun 30 23:59:60 + S 46233294SstasLeap 1995 Dec 31 23:59:60 + S 47233294SstasLeap 1997 Jun 30 23:59:60 + S 48233294SstasLeap 1998 Dec 31 23:59:60 + S 49233294SstasLeap 2005 Dec 31 23:59:60 + S 50233294SstasLeap 2008 Dec 31 23:59:60 + S 51233294Sstas 52233294Sstas# INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) 53233294Sstas# 54233294Sstas# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE 55233294Sstas# 56233294Sstas# SERVICE DE LA ROTATION TERRESTRE 57233294Sstas# OBSERVATOIRE DE PARIS 58233294Sstas# 61, Av. de l'Observatoire 75014 PARIS (France) 59233294Sstas# Tel. : 33 (0) 1 40 51 22 26 60233294Sstas# FAX : 33 (0) 1 40 51 22 91 61233294Sstas# e-mail : services.iers@obspm.fr 62233294Sstas# http://hpiers.obspm.fr/eop-pc 63233294Sstas# 64233294Sstas# Paris, 15 January 2009 65233294Sstas# 66233294Sstas# Bulletin C 37 67233294Sstas# 68233294Sstas# To authorities responsible 69233294Sstas# for the measurement and 70233294Sstas# distribution of time 71233294Sstas# 72233294Sstas# NO positive leap second will be introduced at the end of June 2009. 73233294Sstas# The difference between Coordinated Universal Time UTC and the 74233294Sstas# International Atomic Time TAI is : 75233294Sstas# 76233294Sstas# from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s 77233294Sstas# 78233294Sstas# Leap seconds can be introduced in UTC at the end of the months of December 79233294Sstas# or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every 80233294Sstas# six months, either to announce a time step in UTC or to confirm that there 81233294Sstas# will be no time step at the next possible date. 82233294Sstas# 83233294Sstas# Daniel GAMBIS 84233294Sstas# Head 85233294Sstas# Earth Orientation Center of IERS 86233294Sstas# Observatoire de Paris, France 87233294Sstas