| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | # <pre> |
| 2 | # @(#)leapseconds 8.8 |
| 3 | # This file is in the public domain, so clarified as of |
| 4 | # 2009-05-17 by Arthur David Olson. |
| 5 | |
| 6 | # Allowance for leapseconds added to each timezone file. |
| 7 | |
| 8 | # The International Earth Rotation Service periodically uses leap seconds |
| 9 | # to keep UTC to within 0.9 s of UT1 |
| 10 | # (which measures the true angular orientation of the earth in space); see |
| 11 | # Terry J Quinn, The BIPM and the accurate measure of time, |
| 12 | # Proc IEEE 79, 7 (July 1991), 894-905. |
| 13 | # There were no leap seconds before 1972, because the official mechanism |
| 14 | # accounting for the discrepancy between atomic time and the earth's rotation |
| 15 | # did not exist until the early 1970s. |
| 16 | |
| 17 | # The correction (+ or -) is made at the given time, so lines |
| 18 | # will typically look like: |
| 19 | # Leap YEAR MON DAY 23:59:60 + R/S |
| 20 | # or |
| 21 | # Leap YEAR MON DAY 23:59:59 - R/S |
| 22 | |
| 23 | # If the leapsecond is Rolling (R) the given time is local time |
| 24 | # If the leapsecond is Stationary (S) the given time is UTC |
| 25 | |
| 26 | # Leap YEAR MONTH DAY HH:MM:SS CORR R/S |
| 27 | Leap 1972 Jun 30 23:59:60 + S |
| 28 | Leap 1972 Dec 31 23:59:60 + S |
| 29 | Leap 1973 Dec 31 23:59:60 + S |
| 30 | Leap 1974 Dec 31 23:59:60 + S |
| 31 | Leap 1975 Dec 31 23:59:60 + S |
| 32 | Leap 1976 Dec 31 23:59:60 + S |
| 33 | Leap 1977 Dec 31 23:59:60 + S |
| 34 | Leap 1978 Dec 31 23:59:60 + S |
| 35 | Leap 1979 Dec 31 23:59:60 + S |
| 36 | Leap 1981 Jun 30 23:59:60 + S |
| 37 | Leap 1982 Jun 30 23:59:60 + S |
| 38 | Leap 1983 Jun 30 23:59:60 + S |
| 39 | Leap 1985 Jun 30 23:59:60 + S |
| 40 | Leap 1987 Dec 31 23:59:60 + S |
| 41 | Leap 1989 Dec 31 23:59:60 + S |
| 42 | Leap 1990 Dec 31 23:59:60 + S |
| 43 | Leap 1992 Jun 30 23:59:60 + S |
| 44 | Leap 1993 Jun 30 23:59:60 + S |
| 45 | Leap 1994 Jun 30 23:59:60 + S |
| 46 | Leap 1995 Dec 31 23:59:60 + S |
| 47 | Leap 1997 Jun 30 23:59:60 + S |
| 48 | Leap 1998 Dec 31 23:59:60 + S |
| 49 | Leap 2005 Dec 31 23:59:60 + S |
| 50 | Leap 2008 Dec 31 23:59:60 + S |
| 51 | |
| 52 | # INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) |
| 53 | # |
| 54 | # SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE |
| 55 | # |
| 56 | # SERVICE DE LA ROTATION TERRESTRE |
| 57 | # OBSERVATOIRE DE PARIS |
| 58 | # 61, Av. de l'Observatoire 75014 PARIS (France) |
| 59 | # Tel. : 33 (0) 1 40 51 22 29 |
| 60 | # FAX : 33 (0) 1 40 51 22 91 |
| 61 | # Internet : services.iers@obspm.fr |
| 62 | # |
| 63 | # Paris, 15 January 2009 |
| 64 | # |
| 65 | # Bulletin C 37 |
| 66 | # |
| 67 | # To authorities responsible |
| 68 | # for the measurement and |
| 69 | # distribution of time |
| 70 | # |
| 71 | # INFORMATION ON UTC - TAI |
| 72 | # |
| 73 | # NO positive leap second will be introduced at the end of June 2009. |
| 74 | # The difference between Coordinated Universal Time UTC and the |
| 75 | # International Atomic Time TAI is : |
| 76 | # |
| 77 | # from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s |
| 78 | # |
| 79 | # Leap seconds can be introduced in UTC at the end of the months of December |
| 80 | # or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every |
| 81 | # six months, either to announce a time step in UTC, or to confirm that there |
| 82 | # will be no time step at the next possible date. |
| 83 | # |
| 84 | # Daniel GAMBIS |
| 85 | # Head |
| 86 | # Earth Orientation Center of the IERS |
| 87 | # Observatoire de Paris, France |