# <pre> # @(#)leapseconds 8.10 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. # Allowance for leapseconds added to each timezone file. # The International Earth Rotation Service periodically uses leap seconds # to keep UTC to within 0.9 s of UT1 # (which measures the true angular orientation of the earth in space); see # Terry J Quinn, The BIPM and the accurate measure of time, # Proc IEEE 79, 7 (July 1991), 894-905. # There were no leap seconds before 1972, because the official mechanism # accounting for the discrepancy between atomic time and the earth's rotation # did not exist until the early 1970s. # The correction (+ or -) is made at the given time, so lines # will typically look like: # Leap YEAR MON DAY 23:59:60 + R/S # or # Leap YEAR MON DAY 23:59:59 - R/S # If the leapsecond is Rolling (R) the given time is local time # If the leapsecond is Stationary (S) the given time is UTC # Leap YEAR MONTH DAY HH:MM:SS CORR R/S Leap 1972 Jun 30 23:59:60 + S Leap 1972 Dec 31 23:59:60 + S Leap 1973 Dec 31 23:59:60 + S Leap 1974 Dec 31 23:59:60 + S Leap 1975 Dec 31 23:59:60 + S Leap 1976 Dec 31 23:59:60 + S Leap 1977 Dec 31 23:59:60 + S Leap 1978 Dec 31 23:59:60 + S Leap 1979 Dec 31 23:59:60 + S Leap 1981 Jun 30 23:59:60 + S Leap 1982 Jun 30 23:59:60 + S Leap 1983 Jun 30 23:59:60 + S Leap 1985 Jun 30 23:59:60 + S Leap 1987 Dec 31 23:59:60 + S Leap 1989 Dec 31 23:59:60 + S Leap 1990 Dec 31 23:59:60 + S Leap 1992 Jun 30 23:59:60 + S Leap 1993 Jun 30 23:59:60 + S Leap 1994 Jun 30 23:59:60 + S Leap 1995 Dec 31 23:59:60 + S Leap 1997 Jun 30 23:59:60 + S Leap 1998 Dec 31 23:59:60 + S Leap 2005 Dec 31 23:59:60 + S Leap 2008 Dec 31 23:59:60 + S # INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) # # SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE # # SERVICE DE LA ROTATION TERRESTRE # OBSERVATOIRE DE PARIS # 61, Av. de l'Observatoire 75014 PARIS (France) # Tel. : 33 (0) 1 40 51 22 26 # FAX : 33 (0) 1 40 51 22 91 # Internet : services.iers@obspm.fr # # Paris, 14 July 2010 # # Bulletin C 40 # # To authorities responsible # for the measurement and # distribution of time # # INFORMATION ON UTC - TAI # # NO positive leap second will be introduced at the end of December 2010. # The difference between Coordinated Universal Time UTC and the # International Atomic Time TAI is : # # from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s # # Leap seconds can be introduced in UTC at the end of the months of December # or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every # six months, either to announce a time step in UTC, or to confirm that there # will be no time step at the next possible date. # # Daniel GAMBIS # Director # Earth Orientation Center of IERS # Observatoire de Paris, France