11315084cSEdwin Groothuis# <pre> 2*aad8a35cSEdwin Groothuis# @(#)leapseconds 8.13 31315084cSEdwin Groothuis# This file is in the public domain, so clarified as of 41315084cSEdwin Groothuis# 2009-05-17 by Arthur David Olson. 51315084cSEdwin Groothuis 61315084cSEdwin Groothuis# Allowance for leapseconds added to each timezone file. 71315084cSEdwin Groothuis 81315084cSEdwin Groothuis# The International Earth Rotation Service periodically uses leap seconds 91315084cSEdwin Groothuis# to keep UTC to within 0.9 s of UT1 101315084cSEdwin Groothuis# (which measures the true angular orientation of the earth in space); see 111315084cSEdwin Groothuis# Terry J Quinn, The BIPM and the accurate measure of time, 121315084cSEdwin Groothuis# Proc IEEE 79, 7 (July 1991), 894-905. 131315084cSEdwin Groothuis# There were no leap seconds before 1972, because the official mechanism 141315084cSEdwin Groothuis# accounting for the discrepancy between atomic time and the earth's rotation 151315084cSEdwin Groothuis# did not exist until the early 1970s. 161315084cSEdwin Groothuis 171315084cSEdwin Groothuis# The correction (+ or -) is made at the given time, so lines 181315084cSEdwin Groothuis# will typically look like: 191315084cSEdwin Groothuis# Leap YEAR MON DAY 23:59:60 + R/S 201315084cSEdwin Groothuis# or 211315084cSEdwin Groothuis# Leap YEAR MON DAY 23:59:59 - R/S 221315084cSEdwin Groothuis 231315084cSEdwin Groothuis# If the leapsecond is Rolling (R) the given time is local time 241315084cSEdwin Groothuis# If the leapsecond is Stationary (S) the given time is UTC 251315084cSEdwin Groothuis 261315084cSEdwin Groothuis# Leap YEAR MONTH DAY HH:MM:SS CORR R/S 271315084cSEdwin GroothuisLeap 1972 Jun 30 23:59:60 + S 281315084cSEdwin GroothuisLeap 1972 Dec 31 23:59:60 + S 291315084cSEdwin GroothuisLeap 1973 Dec 31 23:59:60 + S 301315084cSEdwin GroothuisLeap 1974 Dec 31 23:59:60 + S 311315084cSEdwin GroothuisLeap 1975 Dec 31 23:59:60 + S 321315084cSEdwin GroothuisLeap 1976 Dec 31 23:59:60 + S 331315084cSEdwin GroothuisLeap 1977 Dec 31 23:59:60 + S 341315084cSEdwin GroothuisLeap 1978 Dec 31 23:59:60 + S 351315084cSEdwin GroothuisLeap 1979 Dec 31 23:59:60 + S 361315084cSEdwin GroothuisLeap 1981 Jun 30 23:59:60 + S 371315084cSEdwin GroothuisLeap 1982 Jun 30 23:59:60 + S 381315084cSEdwin GroothuisLeap 1983 Jun 30 23:59:60 + S 391315084cSEdwin GroothuisLeap 1985 Jun 30 23:59:60 + S 401315084cSEdwin GroothuisLeap 1987 Dec 31 23:59:60 + S 411315084cSEdwin GroothuisLeap 1989 Dec 31 23:59:60 + S 421315084cSEdwin GroothuisLeap 1990 Dec 31 23:59:60 + S 431315084cSEdwin GroothuisLeap 1992 Jun 30 23:59:60 + S 441315084cSEdwin GroothuisLeap 1993 Jun 30 23:59:60 + S 451315084cSEdwin GroothuisLeap 1994 Jun 30 23:59:60 + S 461315084cSEdwin GroothuisLeap 1995 Dec 31 23:59:60 + S 471315084cSEdwin GroothuisLeap 1997 Jun 30 23:59:60 + S 481315084cSEdwin GroothuisLeap 1998 Dec 31 23:59:60 + S 491315084cSEdwin GroothuisLeap 2005 Dec 31 23:59:60 + S 501315084cSEdwin GroothuisLeap 2008 Dec 31 23:59:60 + S 51*aad8a35cSEdwin GroothuisLeap 2012 Jun 30 23:59:60 + S 521315084cSEdwin Groothuis 531315084cSEdwin Groothuis# INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) 541315084cSEdwin Groothuis# 551315084cSEdwin Groothuis# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE 561315084cSEdwin Groothuis# 57*aad8a35cSEdwin Groothuis# 581315084cSEdwin Groothuis# SERVICE DE LA ROTATION TERRESTRE 591315084cSEdwin Groothuis# OBSERVATOIRE DE PARIS 601315084cSEdwin Groothuis# 61, Av. de l'Observatoire 75014 PARIS (France) 61*aad8a35cSEdwin Groothuis# Tel. : 33 (0) 1 40 51 22 26 621315084cSEdwin Groothuis# FAX : 33 (0) 1 40 51 22 91 63*aad8a35cSEdwin Groothuis# e-mail : (E-Mail Removed) 64*aad8a35cSEdwin Groothuis# http://hpiers.obspm.fr/eop-pc 651315084cSEdwin Groothuis# 66*aad8a35cSEdwin Groothuis# Paris, 5 January 2012 671315084cSEdwin Groothuis# 68*aad8a35cSEdwin Groothuis# 69*aad8a35cSEdwin Groothuis# Bulletin C 43 701315084cSEdwin Groothuis# 711315084cSEdwin Groothuis# To authorities responsible 721315084cSEdwin Groothuis# for the measurement and 731315084cSEdwin Groothuis# distribution of time 741315084cSEdwin Groothuis# 751315084cSEdwin Groothuis# 76*aad8a35cSEdwin Groothuis# UTC TIME STEP 77*aad8a35cSEdwin Groothuis# on the 1st of July 2012 781315084cSEdwin Groothuis# 79*aad8a35cSEdwin Groothuis# 80*aad8a35cSEdwin Groothuis# A positive leap second will be introduced at the end of June 2012. 81*aad8a35cSEdwin Groothuis# The sequence of dates of the UTC second markers will be: 82*aad8a35cSEdwin Groothuis# 83*aad8a35cSEdwin Groothuis# 2012 June 30, 23h 59m 59s 84*aad8a35cSEdwin Groothuis# 2012 June 30, 23h 59m 60s 85*aad8a35cSEdwin Groothuis# 2012 July 1, 0h 0m 0s 86*aad8a35cSEdwin Groothuis# 87*aad8a35cSEdwin Groothuis# The difference between UTC and the International Atomic Time TAI is: 88*aad8a35cSEdwin Groothuis# 89*aad8a35cSEdwin Groothuis# from 2009 January 1, 0h UTC, to 2012 July 1 0h UTC : UTC-TAI = - 34s 90*aad8a35cSEdwin Groothuis# from 2012 July 1, 0h UTC, until further notice : UTC-TAI = - 35s 911315084cSEdwin Groothuis# 921315084cSEdwin Groothuis# Leap seconds can be introduced in UTC at the end of the months of December 931315084cSEdwin Groothuis# or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every 94*aad8a35cSEdwin Groothuis# six months, either to announce a time step in UTC or to confirm that there 951315084cSEdwin Groothuis# will be no time step at the next possible date. 961315084cSEdwin Groothuis# 97*aad8a35cSEdwin Groothuis# 981315084cSEdwin Groothuis# Daniel GAMBIS 99f2ad6fdcSEdwin Groothuis# Head 100*aad8a35cSEdwin Groothuis# Earth Orientation Center of IERS 1011315084cSEdwin Groothuis# Observatoire de Paris, France 102