leapseconds revision 166422 
1# @(#)leapseconds	8.1
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# Internet  : services.iers@obspm.fr
58#
59#						 Paris, 1 February 2007
60#
61#
62#						 Bulletin C 33
63#
64#						 To authorities responsible
65#
66#						 for the measurement and
67#						 distribution of time
68#
69#
70#
71#
72#
73#			    INFORMATION ON UTC - TAI
74#
75#
76#  NO positive leap second will be introduced at the end of June 2007.
77#  The difference between Coordinated Universal Time UTC and the
78#  International Atomic Time TAI is :
79#
80#      from 2006 January 1, 0h UTC, until further notice : UTC-TAI = -33 s
81#
82#  Leap seconds can be introduced in UTC at the end of the months of December
83#  or June,  depending on the evolution of UT1-TAI. Bulletin C is mailed every
84#  six months, either to announce a time step in UTC, or to confirm that there
85#  will be no time step at the next possible date.
86#
87#
88#					     Daniel GAMBIS
89#					     Director
90#					     Earth Orientation Center of IERS
91#					     Observatoire de Paris, France
92#
93