leapseconds revision 93799
193799Swollman# @(#)leapseconds 7.15 275267Swollman 32742Swollman# Allowance for leapseconds added to each timezone file. 42742Swollman 52742Swollman# The International Earth Rotation Service periodically uses leap seconds 658787Sru# to keep UTC to within 0.9 s of UT1 758787Sru# (which measures the true angular orientation of the earth in space); see 82742Swollman# Terry J Quinn, The BIPM and the accurate measure of time, 92742Swollman# Proc IEEE 79, 7 (July 1991), 894-905. 102742Swollman# There were no leap seconds before 1972, because the official mechanism 112742Swollman# accounting for the discrepancy between atomic time and the earth's rotation 122742Swollman# did not exist until the early 1970s. 132742Swollman 142742Swollman# The correction (+ or -) is made at the given time, so lines 152742Swollman# will typically look like: 162742Swollman# Leap YEAR MON DAY 23:59:60 + R/S 172742Swollman# or 182742Swollman# Leap YEAR MON DAY 23:59:59 - R/S 192742Swollman 202742Swollman# If the leapsecond is Rolling (R) the given time is local time 2143014Swollman# If the leapsecond is Stationary (S) the given time is UTC 222742Swollman 232742Swollman# Leap YEAR MONTH DAY HH:MM:SS CORR R/S 242742SwollmanLeap 1972 Jun 30 23:59:60 + S 252742SwollmanLeap 1972 Dec 31 23:59:60 + S 262742SwollmanLeap 1973 Dec 31 23:59:60 + S 272742SwollmanLeap 1974 Dec 31 23:59:60 + S 282742SwollmanLeap 1975 Dec 31 23:59:60 + S 292742SwollmanLeap 1976 Dec 31 23:59:60 + S 302742SwollmanLeap 1977 Dec 31 23:59:60 + S 312742SwollmanLeap 1978 Dec 31 23:59:60 + S 322742SwollmanLeap 1979 Dec 31 23:59:60 + S 332742SwollmanLeap 1981 Jun 30 23:59:60 + S 342742SwollmanLeap 1982 Jun 30 23:59:60 + S 352742SwollmanLeap 1983 Jun 30 23:59:60 + S 362742SwollmanLeap 1985 Jun 30 23:59:60 + S 372742SwollmanLeap 1987 Dec 31 23:59:60 + S 382742SwollmanLeap 1989 Dec 31 23:59:60 + S 392742SwollmanLeap 1990 Dec 31 23:59:60 + S 402742SwollmanLeap 1992 Jun 30 23:59:60 + S 412742SwollmanLeap 1993 Jun 30 23:59:60 + S 422742SwollmanLeap 1994 Jun 30 23:59:60 + S 4339871SphkLeap 1995 Dec 31 23:59:60 + S 4439871SphkLeap 1997 Jun 30 23:59:60 + S 4539898SphkLeap 1998 Dec 31 23:59:60 + S 4686222Swollman 4786222Swollman# INTERNATIONAL EARTH ROTATION SERVICE (IERS) 4886222Swollman# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE 4975267Swollman# 5075267Swollman# SERVICE DE LA ROTATION TERRESTRE 5175267Swollman# OBSERVATOIRE DE PARIS 5275267Swollman# 61, Av. de l'Observatoire 75014 PARIS (France) 5375267Swollman# Tel. : 33 (0) 1 40 51 22 26 5475267Swollman# FAX : 33 (0) 1 40 51 22 91 5575267Swollman# Internet : iers@obspm.fr 5675267Swollman# 5793799Swollman# Paris, 14 January 2002 5875267Swollman# 5993799Swollman# Bulletin C 23 6075267Swollman# 6193799Swollman# To authorities responsible 6293799Swollman# for the measurement and 6393799Swollman# distribution of time 6475267Swollman# 6593799Swollman# INFORMATION ON UTC - TAI 6675267Swollman# 6793799Swollman# NO positive leap second will be introduced at the end of June 2002. 6893799Swollman# The difference between UTC and the International Atomic Time TAI is : 6993799Swollman# 7093799Swollman# from 1999 January 1, 0h UTC, until further notice : UTC-TAI = -32 s 7186222Swollman# 7293799Swollman# Leap seconds can be introduced in UTC at the end of the months of December 7393799Swollman# or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every 7493799Swollman# six months, either to announce a time step in UTC, or to confirm that there 7593799Swollman# will be no time step at the next possible date. 7686222Swollman# 7793799Swollman# Daniel GAMBIS 7893799Swollman# Director 7993799Swollman# Earth Orientation Center of IERS 8093799Swollman# Observatoire de Paris, France 81