timezone/leapseconds

   1 # <pre>
   2 # @(#)leapseconds       8.8
   3 # This file is in the public domain, so clarified as of
   4 # 2009-05-17 by Arthur David Olson.
   5
   6 # Allowance for leapseconds added to each timezone file.
   7
   8 # The International Earth Rotation Service periodically uses leap seconds
   9 # to keep UTC to within 0.9 s of UT1
  10 # (which measures the true angular orientation of the earth in space); see
  11 # Terry J Quinn, The BIPM and the accurate measure of time,
  12 # Proc IEEE 79, 7 (July 1991), 894-905.
  13 # There were no leap seconds before 1972, because the official mechanism
  14 # accounting for the discrepancy between atomic time and the earth's rotation
  15 # did not exist until the early 1970s.
  16
  17 # The correction (+ or -) is made at the given time, so lines
  18 # will typically look like:
  19 #       Leap    YEAR    MON     DAY     23:59:60        +       R/S
  20 # or
  21 #       Leap    YEAR    MON     DAY     23:59:59        -       R/S
  22
  23 # If the leapsecond is Rolling (R) the given time is local time
  24 # If the leapsecond is Stationary (S) the given time is UTC
  25
  26 # Leap  YEAR    MONTH   DAY     HH:MM:SS        CORR    R/S
  27 Leap    1972    Jun     30      23:59:60        +       S
  28 Leap    1972    Dec     31      23:59:60        +       S
  29 Leap    1973    Dec     31      23:59:60        +       S
  30 Leap    1974    Dec     31      23:59:60        +       S
  31 Leap    1975    Dec     31      23:59:60        +       S
  32 Leap    1976    Dec     31      23:59:60        +       S
  33 Leap    1977    Dec     31      23:59:60        +       S
  34 Leap    1978    Dec     31      23:59:60        +       S
  35 Leap    1979    Dec     31      23:59:60        +       S
  36 Leap    1981    Jun     30      23:59:60        +       S
  37 Leap    1982    Jun     30      23:59:60        +       S
  38 Leap    1983    Jun     30      23:59:60        +       S
  39 Leap    1985    Jun     30      23:59:60        +       S
  40 Leap    1987    Dec     31      23:59:60        +       S
  41 Leap    1989    Dec     31      23:59:60        +       S
  42 Leap    1990    Dec     31      23:59:60        +       S
  43 Leap    1992    Jun     30      23:59:60        +       S
  44 Leap    1993    Jun     30      23:59:60        +       S
  45 Leap    1994    Jun     30      23:59:60        +       S
  46 Leap    1995    Dec     31      23:59:60        +       S
  47 Leap    1997    Jun     30      23:59:60        +       S
  48 Leap    1998    Dec     31      23:59:60        +       S
  49 Leap    2005    Dec     31      23:59:60        +       S
  50 Leap    2008    Dec     31      23:59:60        +       S
  51
  52 # INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS)
  53 #
  54 # SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE
  55 #
  56 # SERVICE DE LA ROTATION TERRESTRE
  57 # OBSERVATOIRE DE PARIS
  58 # 61, Av. de l'Observatoire 75014 PARIS (France)
  59 # Tel.      : 33 (0) 1 40 51 22 29
  60 # FAX       : 33 (0) 1 40 51 22 91
  61 # Internet  : services.iers@obspm.fr
  62 #
  63 # Paris, 15 January 2009
  64 #
  65 # Bulletin C 37
  66 #
  67 # To authorities responsible
  68 # for the measurement and
  69 # distribution of time
  70 #
  71 # INFORMATION ON UTC - TAI
  72 #
  73 # NO positive leap second will be introduced at the end of June 2009.
  74 # The difference between Coordinated Universal Time UTC and the
  75 # International Atomic Time TAI is :
  76 #
  77 # from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s
  78 #
  79 # Leap seconds can be introduced in UTC at the end of the months of December
  80 # or June,  depending on the evolution of UT1-TAI. Bulletin C is mailed every
  81 # six months, either to announce a time step in UTC, or to confirm that there
  82 # will be no time step at the next possible date.
  83 #
  84 # Daniel GAMBIS
  85 # Head
  86 # Earth Orientation Center of the IERS
  87 # Observatoire de Paris, France