leapseconds revision 180379 
1# @(#)leapseconds	8.5
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
47Leap	2008	Dec	31	23:59:60	+	S
48
49# INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS)
50#
51# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE
52#
53# SERVICE DE LA ROTATION TERRESTRE
54# OBSERVATOIRE DE PARIS				
55# 61, Av. de l'Observatoire 75014 PARIS (France)
56# Tel.      : 33 (0) 1 40 51 22 26
57# FAX       : 33 (0) 1 40 51 22 91
58# Internet  : services.iers@obspm.fr
59#
60# Paris, 4 July 2008
61#
62# Bulletin C 36
63#
64# To authorities responsible		
65# for the measurement and
66# distribution of time	
67#
68# INFORMATION ON UTC - TAI
69#
70#
71# UTC TIME STEP
72# on the 1st of January 2009
73#
74# A positive leap second will be introduced at the end of December 2008.
75# The sequence of dates of the UTC second markers will be:
76#
77#    2008 December 31,     23h 59m 59s
78#    2008 December 31,     23h 59m 60s
79#    2009 January   1,      0h  0m  0s
80# 
81# The difference between UTC and the International Atomic Time TAI is:
82#
83#  from 2006 January 1, 0h UTC, to 2009 January 1  0h UTC  : UTC-TAI = - 33s
84#  from 2009 January 1, 0h UTC, until further notice       : UTC-TAI = - 34s 
85#
86# Leap seconds can be introduced in UTC at the end of the months of December
87# or June,  depending on the evolution of UT1-TAI. Bulletin C is mailed every
88# six months, either to announce a time step in UTC, or to confirm that there
89# will be no time step at the next possible date.
90#
91# Daniel GAMBIS
92# Head			
93# Earth Orientation Center of the IERS
94# Observatoire de Paris, France
95