2
3# Allowance for leapseconds added to each timezone file.
4
5# The International Earth Rotation Service periodically uses leap seconds
6# to keep UTC to within 0.9 s of UT1
7# (which measures the true angular orientation of the earth in space); see
8# Terry J Quinn, The BIPM and the accurate measure of time,
9# Proc IEEE 79, 7 (July 1991), 894-905.
10# There were no leap seconds before 1972, because the official mechanism
11# accounting for the discrepancy between atomic time and the earth's rotation
12# did not exist until the early 1970s.
13
14# The correction (+ or -) is made at the given time, so lines
15# will typically look like:
16# Leap YEAR MON DAY 23:59:60 + R/S
17# or
18# Leap YEAR MON DAY 23:59:59 - R/S
19
20# If the leapsecond is Rolling (R) the given time is local time
21# If the leapsecond is Stationary (S) the given time is UTC
22
23# Leap YEAR MONTH DAY HH:MM:SS CORR R/S
24Leap 1972 Jun 30 23:59:60 + S
25Leap 1972 Dec 31 23:59:60 + S
26Leap 1973 Dec 31 23:59:60 + S
27Leap 1974 Dec 31 23:59:60 + S
28Leap 1975 Dec 31 23:59:60 + S
29Leap 1976 Dec 31 23:59:60 + S
30Leap 1977 Dec 31 23:59:60 + S
31Leap 1978 Dec 31 23:59:60 + S
32Leap 1979 Dec 31 23:59:60 + S
33Leap 1981 Jun 30 23:59:60 + S
34Leap 1982 Jun 30 23:59:60 + S
35Leap 1983 Jun 30 23:59:60 + S
36Leap 1985 Jun 30 23:59:60 + S
37Leap 1987 Dec 31 23:59:60 + S
38Leap 1989 Dec 31 23:59:60 + S
39Leap 1990 Dec 31 23:59:60 + S
40Leap 1992 Jun 30 23:59:60 + S
41Leap 1993 Jun 30 23:59:60 + S
42Leap 1994 Jun 30 23:59:60 + S
43Leap 1995 Dec 31 23:59:60 + S
44Leap 1997 Jun 30 23:59:60 + S
45Leap 1998 Dec 31 23:59:60 + S
46Leap 2005 Dec 31 23:59:60 + S
47
48# INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS)
49#
50# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE
51#
52# SERVICE DE LA ROTATION TERRESTRE
53# OBSERVATOIRE DE PARIS
54# 61, Av. de l'Observatoire 75014 PARIS (France)
55# Tel. : 33 (0) 1 40 51 22 26
56# FAX : 33 (0) 1 40 51 22 91
57# ...
58# http://hpiers.obspm.fr/eop-pc
59#
60# Paris, 4 July 2005
61#
62# Bulletin C 30
63#
64# To authorities responsible
65# for the measurement and
66# distribution of time
67#
68#
69# UTC TIME STEP
70# on the 1st of January 2006
71#
72# A positive leap second will be introduced at the end of December 2005.
73# The sequence of dates of the UTC second markers will be:
74#
75# 2005 December 31, 23h 59m 59s
76# 2005 December 31, 23h 59m 60s
77# 2006 January 1, 0h 0m 0s
78#
79# The difference between UTC and the International Atomic Time TAI is:
80#
81# from 1999 January 1, 0h UTC, to 2006 January 1 0h UTC : UTC-TAI = - 32s
82# from 2006 January 1, 0h UTC, until further notice : UTC-TAI = - 33s
83#
84# Leap seconds can be introduced in UtC at the end of the months of December
85# or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every
86# six months, either to announce a time step in UTC or to confirm that there
87# will be no time step at the next possible date.
88#
89# Daniel GAMBIS
90# Head
91# Earth Orientation Center of IERS
92# Observatoire de Paris, France
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