xref: /freebsd-10.2-release/contrib/tzdata/leapseconds

# @(#)leapseconds	7.17

# Allowance for leapseconds added to each timezone file.

# The International Earth Rotation Service periodically uses leap seconds
# to keep UTC to within 0.9 s of UT1
# (which measures the true angular orientation of the earth in space); see
# Terry J Quinn, The BIPM and the accurate measure of time,
# Proc IEEE 79, 7 (July 1991), 894-905.
# There were no leap seconds before 1972, because the official mechanism
# accounting for the discrepancy between atomic time and the earth's rotation
# did not exist until the early 1970s.

# The correction (+ or -) is made at the given time, so lines
# will typically look like:
#	Leap	YEAR	MON	DAY	23:59:60	+	R/S
# or
#	Leap	YEAR	MON	DAY	23:59:59	-	R/S

# If the leapsecond is Rolling (R) the given time is local time
# If the leapsecond is Stationary (S) the given time is UTC

# Leap	YEAR	MONTH	DAY	HH:MM:SS	CORR	R/S
Leap	1972	Jun	30	23:59:60	+	S
Leap	1972	Dec	31	23:59:60	+	S
Leap	1973	Dec	31	23:59:60	+	S
Leap	1974	Dec	31	23:59:60	+	S
Leap	1975	Dec	31	23:59:60	+	S
Leap	1976	Dec	31	23:59:60	+	S
Leap	1977	Dec	31	23:59:60	+	S
Leap	1978	Dec	31	23:59:60	+	S
Leap	1979	Dec	31	23:59:60	+	S
Leap	1981	Jun	30	23:59:60	+	S
Leap	1982	Jun	30	23:59:60	+	S
Leap	1983	Jun	30	23:59:60	+	S
Leap	1985	Jun	30	23:59:60	+	S
Leap	1987	Dec	31	23:59:60	+	S
Leap	1989	Dec	31	23:59:60	+	S
Leap	1990	Dec	31	23:59:60	+	S
Leap	1992	Jun	30	23:59:60	+	S
Leap	1993	Jun	30	23:59:60	+	S
Leap	1994	Jun	30	23:59:60	+	S
Leap	1995	Dec	31	23:59:60	+	S
Leap	1997	Jun	30	23:59:60	+	S
Leap	1998	Dec	31	23:59:60	+	S
Leap	2005	Dec	31	23:59:60	+	S

# 
# 
# 
#      INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) 
# 
# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE
# 
# SERVICE DE LA ROTATION TERRESTRE
# OBSERVATOIRE DE PARIS                                   
# 61, Av. de l'Observatoire 75014 PARIS (France)
# Tel.      : 33 (0) 1 40 51 22 26
# FAX       : 33 (0) 1 40 51 22 91
# e-mail    : services.iers@obspm.fr
# http://hpiers.obspm.fr/eop-pc
# 
#                                               Paris, 4 July 2005
#                                                            
#                                               Bulletin C 30
#                                 
#                                               To authorities responsible 
# 					      for the measurement and 
# 					      distribution of time                                         
# 
# 
#                                    UTC TIME STEP
#                             on the 1st of January 2006
#                       
# 
#  A positive leap second will be introduced at the end of December 2005.
#  The sequence of dates of the UTC second markers will be:		
# 		
#                           2005 December 31,     23h 59m 59s
#                           2005 December 31,     23h 59m 60s
#                           2006 January   1,      0h  0m  0s
#               
#  The difference between UTC and the International Atomic Time TAI is:
#   
#   from 1999 January 1, 0h UTC, to 2006 January 1  0h UTC  : UTC-TAI = - 32s
#   from 2006 January 1, 0h UTC, until further notice       : UTC-TAI = - 33s
#   
#  Leap seconds can be introduced in UTC at the end of the months of December 
#  or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every 
#  six months, either to announce a time step in UTC or to confirm that there 
#  will be no time step at the next possible date.
#  
# 
# 
#                                               Daniel GAMBIS
#                                               Head		
#                                               Earth Orientation Center of IERS
# 					      Observatoire de Paris, France
#