leapseconds revision 169811
181615Sjake# @(#)leapseconds 8.3 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# ... 49# Sent: Thursday, February 01, 2007 9:49 AM 50# ... 51# Subject: Bulletin C number 33 52# 53# INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) 54# 55# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE 56# 57# SERVICE DE LA ROTATION TERRESTRE 58# OBSERVATOIRE DE PARIS 59# 61, Av. de l'Observatoire 75014 PARIS (France) 60# ... 61# 62# Paris, 1 February 2007 63# Bulletin C 33 64# To authorities responsible 65# for the measurement and 66# distribution of time 67# 68# INFORMATION ON UTC - TAI 69# 70# NO positive leap second will be introduced at the end of June 2007. 71# The difference between Coordinated Universal Time UTC and the 72# International Atomic Time TAI is: 73# from 2006 January 1, 0h UTC, until further notice : UTC-TAI = -33 s 74# Leap seconds can be introduced in UTC at the end of the months of 75# December or June, depending on the evolution of UT1-TAI. Bulletin C is 76# mailed every six months, either to announce a time step in UTC, or to 77# confirm that there will be no time step at the next possible date. 78# 79# Daniel GAMBIS 80# Director 81# Earth Orientation Center of IERS 82# Observatoire de Paris, France 83