leapseconds revision 240461
1192886Sedwin# <pre> 2192886Sedwin# This file is in the public domain, so clarified as of 3192886Sedwin# 2009-05-17 by Arthur David Olson. 475267Swollman 52742Swollman# Allowance for leapseconds added to each timezone file. 62742Swollman 72742Swollman# The International Earth Rotation Service periodically uses leap seconds 858787Sru# to keep UTC to within 0.9 s of UT1 958787Sru# (which measures the true angular orientation of the earth in space); see 102742Swollman# Terry J Quinn, The BIPM and the accurate measure of time, 112742Swollman# Proc IEEE 79, 7 (July 1991), 894-905. 122742Swollman# There were no leap seconds before 1972, because the official mechanism 132742Swollman# accounting for the discrepancy between atomic time and the earth's rotation 142742Swollman# did not exist until the early 1970s. 152742Swollman 162742Swollman# The correction (+ or -) is made at the given time, so lines 172742Swollman# will typically look like: 182742Swollman# Leap YEAR MON DAY 23:59:60 + R/S 192742Swollman# or 202742Swollman# Leap YEAR MON DAY 23:59:59 - R/S 212742Swollman 222742Swollman# If the leapsecond is Rolling (R) the given time is local time 2343014Swollman# If the leapsecond is Stationary (S) the given time is UTC 242742Swollman 252742Swollman# Leap YEAR MONTH DAY HH:MM:SS CORR R/S 262742SwollmanLeap 1972 Jun 30 23:59:60 + S 272742SwollmanLeap 1972 Dec 31 23:59:60 + S 282742SwollmanLeap 1973 Dec 31 23:59:60 + S 292742SwollmanLeap 1974 Dec 31 23:59:60 + S 302742SwollmanLeap 1975 Dec 31 23:59:60 + S 312742SwollmanLeap 1976 Dec 31 23:59:60 + S 322742SwollmanLeap 1977 Dec 31 23:59:60 + S 332742SwollmanLeap 1978 Dec 31 23:59:60 + S 342742SwollmanLeap 1979 Dec 31 23:59:60 + S 352742SwollmanLeap 1981 Jun 30 23:59:60 + S 362742SwollmanLeap 1982 Jun 30 23:59:60 + S 372742SwollmanLeap 1983 Jun 30 23:59:60 + S 382742SwollmanLeap 1985 Jun 30 23:59:60 + S 392742SwollmanLeap 1987 Dec 31 23:59:60 + S 402742SwollmanLeap 1989 Dec 31 23:59:60 + S 412742SwollmanLeap 1990 Dec 31 23:59:60 + S 422742SwollmanLeap 1992 Jun 30 23:59:60 + S 432742SwollmanLeap 1993 Jun 30 23:59:60 + S 442742SwollmanLeap 1994 Jun 30 23:59:60 + S 4539871SphkLeap 1995 Dec 31 23:59:60 + S 4639871SphkLeap 1997 Jun 30 23:59:60 + S 4739898SphkLeap 1998 Dec 31 23:59:60 + S 48147771SphkLeap 2005 Dec 31 23:59:60 + S 49181424SedwinLeap 2008 Dec 31 23:59:60 + S 50233447SedwinLeap 2012 Jun 30 23:59:60 + S 5186222Swollman 52171948Sedwin# INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) 53176974Sedwin# 54136638Swollman# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE 55149514Swollman# 56233447Sedwin# 5775267Swollman# SERVICE DE LA ROTATION TERRESTRE 58181424Sedwin# OBSERVATOIRE DE PARIS 5975267Swollman# 61, Av. de l'Observatoire 75014 PARIS (France) 60233447Sedwin# Tel. : 33 (0) 1 40 51 22 26 61171948Sedwin# FAX : 33 (0) 1 40 51 22 91 62233447Sedwin# e-mail : (E-Mail Removed) 63233447Sedwin# http://hpiers.obspm.fr/eop-pc 64149514Swollman# 65233447Sedwin# Paris, 5 January 2012 66149514Swollman# 67149514Swollman# 68233447Sedwin# Bulletin C 43 69233447Sedwin# 70181424Sedwin# To authorities responsible 71171948Sedwin# for the measurement and 72181424Sedwin# distribution of time 73171948Sedwin# 74171948Sedwin# 75233447Sedwin# UTC TIME STEP 76233447Sedwin# on the 1st of July 2012 77196581Sedwin# 78196581Sedwin# 79233447Sedwin# A positive leap second will be introduced at the end of June 2012. 80240461Sedwin# The sequence of dates of the UTC second markers will be: 81240461Sedwin# 82233447Sedwin# 2012 June 30, 23h 59m 59s 83233447Sedwin# 2012 June 30, 23h 59m 60s 84233447Sedwin# 2012 July 1, 0h 0m 0s 85233447Sedwin# 86233447Sedwin# The difference between UTC and the International Atomic Time TAI is: 87233447Sedwin# 88233447Sedwin# from 2009 January 1, 0h UTC, to 2012 July 1 0h UTC : UTC-TAI = - 34s 89233447Sedwin# from 2012 July 1, 0h UTC, until further notice : UTC-TAI = - 35s 90233447Sedwin# 91171948Sedwin# Leap seconds can be introduced in UTC at the end of the months of December 92233447Sedwin# or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every 93233447Sedwin# six months, either to announce a time step in UTC or to confirm that there 94171948Sedwin# will be no time step at the next possible date. 95171948Sedwin# 96233447Sedwin# 97171948Sedwin# Daniel GAMBIS 98240461Sedwin# Head 99233447Sedwin# Earth Orientation Center of IERS 100171948Sedwin# Observatoire de Paris, France 101