1# @(#)leapseconds 7.17 2 3# Allowance for leapseconds added to each timezone file. 4 5# The International Earth Rotation Service periodically uses leap seconds 6# to keep UTC to within 0.9 s of UT1 7# (which measures the true angular orientation of the earth in space); see 8# Terry J Quinn, The BIPM and the accurate measure of time, 9# Proc IEEE 79, 7 (July 1991), 894-905. 10# There were no leap seconds before 1972, because the official mechanism 11# accounting for the discrepancy between atomic time and the earth's rotation 12# did not exist until the early 1970s. 13 14# The correction (+ or -) is made at the given time, so lines 15# will typically look like: 16# Leap YEAR MON DAY 23:59:60 + R/S 17# or 18# Leap YEAR MON DAY 23:59:59 - R/S 19 20# If the leapsecond is Rolling (R) the given time is local time 21# If the leapsecond is Stationary (S) the given time is UTC 22 23# Leap YEAR MONTH DAY HH:MM:SS CORR R/S 24Leap 1972 Jun 30 23:59:60 + S 25Leap 1972 Dec 31 23:59:60 + S 26Leap 1973 Dec 31 23:59:60 + S 27Leap 1974 Dec 31 23:59:60 + S 28Leap 1975 Dec 31 23:59:60 + S 29Leap 1976 Dec 31 23:59:60 + S 30Leap 1977 Dec 31 23:59:60 + S 31Leap 1978 Dec 31 23:59:60 + S 32Leap 1979 Dec 31 23:59:60 + S 33Leap 1981 Jun 30 23:59:60 + S 34Leap 1982 Jun 30 23:59:60 + S 35Leap 1983 Jun 30 23:59:60 + S 36Leap 1985 Jun 30 23:59:60 + S 37Leap 1987 Dec 31 23:59:60 + S 38Leap 1989 Dec 31 23:59:60 + S 39Leap 1990 Dec 31 23:59:60 + S 40Leap 1992 Jun 30 23:59:60 + S 41Leap 1993 Jun 30 23:59:60 + S 42Leap 1994 Jun 30 23:59:60 + S 43Leap 1995 Dec 31 23:59:60 + S 44Leap 1997 Jun 30 23:59:60 + S 45Leap 1998 Dec 31 23:59:60 + S 46Leap 2005 Dec 31 23:59:60 + S 47 48# INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) 49# 50#SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE 51# 52#SERVICE DE LA ROTATION TERRESTRE 53#OBSERVATOIRE DE PARIS 54#61, Av. de l'Observatoire 75014 PARIS (France) 55#Tel. : 33 (0) 1 40 51 22 26 56#FAX : 33 (0) 1 40 51 22 91 57#e-mail : services.iers@obspm.fr 58#http://hpiers.obspm.fr/eop-pc 59# 60# Paris, 4 July 2005 61# 62# Bulletin C 30 63# 64# To authorities responsible 65# for the measurement and 66# distribution of time 67# 68# 69# UTC TIME STEP 70# on the 1st of January 2006 71# 72# 73# A positive leap second will be introduced at the end of December 2005. 74# The sequence of dates of the UTC second markers will be: 75# 76# 2005 December 31, 23h 59m 59s 77# 2005 December 31, 23h 59m 60s 78# 2006 January 1, 0h 0m 0s 79# 80# The difference between UTC and the International Atomic Time TAI is: 81# 82# from 1999 January 1, 0h UTC, to 2006 January 1 0h UTC : UTC-TAI = - 32s 83# from 2006 January 1, 0h UTC, until further notice : UTC-TAI = - 33s 84# 85# Leap seconds can be introduced in UTC at the end of the months of December 86# or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every 87# six months, either to announce a time step in UTC or to confirm that there 88# will be no time step at the next possible date. 89# 90# 91# 92# Daniel GAMBIS 93# Head 94# Earth Orientation Center of IERS 95# Observatoire de Paris, France 96