2000-03-29 14:01:46 +00:00
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# @(#)leapseconds 7.12
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# $FreeBSD$
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1994-09-13 21:50:18 +00:00
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# Allowance for leapseconds added to each timezone file.
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# The International Earth Rotation Service periodically uses leap seconds
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2000-03-29 14:01:46 +00:00
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# to keep UTC to within 0.9 s of UT1
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# (which measures the true angular orientation of the earth in space); see
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1994-09-13 21:50:18 +00:00
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# Terry J Quinn, The BIPM and the accurate measure of time,
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# Proc IEEE 79, 7 (July 1991), 894-905.
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# There were no leap seconds before 1972, because the official mechanism
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# accounting for the discrepancy between atomic time and the earth's rotation
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# did not exist until the early 1970s.
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# The correction (+ or -) is made at the given time, so lines
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# will typically look like:
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# Leap YEAR MON DAY 23:59:60 + R/S
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# or
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# Leap YEAR MON DAY 23:59:59 - R/S
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# If the leapsecond is Rolling (R) the given time is local time
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1999-01-21 21:55:55 +00:00
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# If the leapsecond is Stationary (S) the given time is UTC
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1994-09-13 21:50:18 +00:00
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# Leap YEAR MONTH DAY HH:MM:SS CORR R/S
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Leap 1972 Jun 30 23:59:60 + S
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Leap 1972 Dec 31 23:59:60 + S
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Leap 1973 Dec 31 23:59:60 + S
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Leap 1974 Dec 31 23:59:60 + S
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Leap 1975 Dec 31 23:59:60 + S
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Leap 1976 Dec 31 23:59:60 + S
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Leap 1977 Dec 31 23:59:60 + S
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Leap 1978 Dec 31 23:59:60 + S
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Leap 1979 Dec 31 23:59:60 + S
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Leap 1981 Jun 30 23:59:60 + S
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Leap 1982 Jun 30 23:59:60 + S
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Leap 1983 Jun 30 23:59:60 + S
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Leap 1985 Jun 30 23:59:60 + S
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Leap 1987 Dec 31 23:59:60 + S
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Leap 1989 Dec 31 23:59:60 + S
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Leap 1990 Dec 31 23:59:60 + S
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Leap 1992 Jun 30 23:59:60 + S
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Leap 1993 Jun 30 23:59:60 + S
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Leap 1994 Jun 30 23:59:60 + S
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INTERNATIONAL EARTH ROTATION SERVICE (IERS)
SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE
BUREAU CENTRAL DE L'IERS
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
Internet : iers@obspm.fr
Paris, 17 July 1998
Bulletin C 16
To authorities responsible for
the measurement and distribution
of time
UTC TIME STEP
on the 1st of January 1999
A positive leap second will be introduced at the end of December 1998.
The sequence of dates of the UTC second markers will be:
1998 December 31, 23h 59m 59s
1998 December 31, 23h 59m 60s
1999 January 1, 0h 0m 0s
The difference between UTC and the International Atomic Time TAI is:
from 1997 July 1, 0h UTC, to 1999 January 1, 0h UTC : UTC-TAI = - 31s
from 1999 January 1, 0h UTC, until further notice : UTC-TAI = - 32s
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 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
Director
Central Bureau of IERS
1998-10-01 20:42:03 +00:00
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Leap 1995 Dec 31 23:59:60 + S
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Leap 1997 Jun 30 23:59:60 + S
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1998-10-02 17:08:35 +00:00
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Leap 1998 Dec 31 23:59:60 + S
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