8eaebe2007-02-01Henrik Grubbström (Grubba) # @(#)leapseconds 8.1
c0dbee2000-08-01Mirar (Pontus Hagland)  # 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
8eaebe2007-02-01Henrik Grubbström (Grubba) Leap 2005 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 # ... # http://hpiers.obspm.fr/eop-pc # # Paris, 4 July 2005 # # Bulletin C 30 # # To authorities responsible # for the measurement and # distribution of time # # # UTC TIME STEP # on the 1st of January 2006 # # A positive leap second will be introduced at the end of December 2005. # The sequence of dates of the UTC second markers will be: # # 2005 December 31, 23h 59m 59s # 2005 December 31, 23h 59m 60s # 2006 January 1, 0h 0m 0s # # The difference between UTC and the International Atomic Time TAI is: # # from 1999 January 1, 0h UTC, to 2006 January 1 0h UTC : UTC-TAI = - 32s # from 2006 January 1, 0h UTC, until further notice : UTC-TAI = - 33s # # 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 # Head # Earth Orientation Center of IERS # Observatoire de Paris, France