leapseconds revision 171424 
1# @(#)leapseconds	8.3
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# ...
49# Date: Thu, 28 Jun 2007 14:36:55 +0200
50# Message-Id: <200706281236.l5SCatpA020400@callisto.obspm.fr>
51# ...
52# Subject: Bulletin C number 34
53# ...
54# 	INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS)
55#
56# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE
57#
58# SERVICE DE LA ROTATION TERRESTRE
59# OBSERVATOIRE DE PARIS
60# 61, Av. de l'Observatoire 75014 PARIS (France)
61# ...
62#
63#                                                Paris, 28 June 2007
64#                                                Bulletin C 34
65#                                                To authorities responsible
66#                                                for the measurement and
67#                                                distribution of time
68#
69#                           INFORMATION ON UTC - TAI
70#
71# NO positive leap second will be introduced at the end of December 2007.
72# The difference between Coordinated Universal Time UTC and the
73# International Atomic Time TAI is:
74#      from 2006 January 1, 0h UTC, until further notice : UTC-TAI = -33 s
75# Leap seconds can be introduced in UTC at the end of the months of
76# December  or June,  depending on the evolution of UT1-TAI. Bulletin C is
77# mailed every  six months, either to announce a time step in UTC, or to
78# confirm that there  will be no time step at the next possible date.
79#
80# 				Daniel GAMBIS
81# 				Director
82# 				Earth Orientation Center of IERS
83# 				Observatoire de Paris, France
84