leapseconds revision 86222
186222Swollman# @(#)leapseconds 7.14 275267Swollman 358787Sru# $FreeBSD: head/share/zoneinfo/leapseconds 86222 2001-11-09 19:17:59Z wollman $ 42742Swollman 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 4886222Swollman 4986222Swollman# INTERNATIONAL EARTH ROTATION SERVICE (IERS) 5086222Swollman# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE 5175267Swollman# 5275267Swollman# SERVICE DE LA ROTATION TERRESTRE 5375267Swollman# OBSERVATOIRE DE PARIS 5475267Swollman# 61, Av. de l'Observatoire 75014 PARIS (France) 5575267Swollman# Tel. : 33 (0) 1 40 51 22 26 5675267Swollman# FAX : 33 (0) 1 40 51 22 91 5775267Swollman# Internet : iers@obspm.fr 5875267Swollman# 5986222Swollman# Paris, 25 June 2001 6075267Swollman# 6186222Swollman# Bulletin C 22 6275267Swollman# 6386222Swollman# To authorities responsible 6486222Swollman# for the measurement and 6586222Swollman# distribution of time 6675267Swollman# 6786222Swollman# INFORMATION ON UTC - TAI 6875267Swollman# 6986222Swollman# NO positive leap second will be introduced at the end of December 2001. 7086222Swollman# The difference between UTC and the International Atomic Time TAI is : 7186222Swollman# 7286222Swollman# from 1999 January 1, 0h UTC, until further notice : UTC-TAI = -32 s 7386222Swollman# 7486222Swollman# Leap seconds can be introduced in UTC at the end of the months of December 7586222Swollman# or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every 7686222Swollman# six months, either to announce a time step in UTC, or to confirm that there 7786222Swollman# will be no time step at the next possible date. 7886222Swollman# 7986222Swollman# Daniel GAMBIS 8086222Swollman# Director 8186222Swollman# Earth Orientation Center of IERS 82