[tz] Bulletin C number 57

Thu Jan 17 22:51:40 UTC 2019

On Tue Jan  8 01:32:04 UTC 2019, Paul Eggert wrote:> In the meantime perhaps we could forge the NIST leap-seconds.list file 
> (including a comment that it's a forgery and why we're doing the 
> forgery), and then substitute the real thing whenever it shows up. I'd 
> rather have a script to do that than do it by hand, though. We'd need 
> that script anyway if we start basing our distribution on the IERS file, 
> as so many users now grab the NIST file from us rather than from the NIST.Your wish is my command....

#    -=*( This file is in the public domain )*=-
# This NTP leap-second file was created with data obtained from
# the United States Naval Observatory (USNO) MAIA FTP server.
#
#  Find it at: <ftp://maia.usno.navy.mil/ser7/leapsec.dat>

# Updated using information from IERS Bulletin C 57 (7 Jan 2019)
# Found at <ftp://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat>
#
# This file is not a forgery, per se, but it is created
# by some one/thing other than a national metrology lab.

# It is necessitated by a current US government shutdown
# and the resulting lack of an NIST generated file.
#
# UTC is a time scale based upon standard international (SI)
# seconds and derived from Temps Atomique International (TAI).
#
# Leap seconds are an official correction to UTC to keep it
# within 0.9 seconds of UT1; yet another time standard
# based upon the orientation of the earth in space.
#
# These data, kept in "leap-seconds.list", are used by the
# Network Time Protocol daemon (NTPd) to determine when to
# apply leap seconds to Coordinated Universal Time (UTC).
# "leap-seconds.list" is a symbolic link to the actual
# file name, leap-seconds.xxxxxxxxxx, where xxxxxxxxxx
# is derived from the NTP update timestamp (below).
#
# Theoretically, a leap second may be positive or negative.
# Realistically, negative leap seconds are unlikely to occur.
#
# All timestamps in this leap seconds file are encoded using the
# NTP epoch.  These timestamps represent the number of seconds
# since 1 Jan 1900 0:00:00.  This is Modified Julian Date (MJD)
# 15020 and Julian Date 2415020.5.  There will be an unsigned
# 32-bit overflow to the second NTP era in 2036 (07 Feb 2036
# 06:28:16 UTC to be precise).
#
# A leap second datum consists of an NTP timestamp and the
# number of seconds difference between TAI and UTC (e.g.
# currently TAI-UTC is 37).  UTC was established at midnight on
# 1 Jan 1972 with TAI-UTC started at 10.  There was no mechanism
# prior to that time defining when to apply leap seconds.
#
# Note: the first datum in the leap-seconds.list file is *not*
# a leap-second; it denotes the definition of the UTC timescale.
#
# Leap-seconds rules are establish in:
#
# International Telecommunications Union-Regulation (ITU-R)
# 460-6, Annex 1, Section 2.
#
#   <http://www.itu.int/rec/R-REC-TF.460-6-200202-I/>
#
# NTP Leap second files have an update time (#$).  This is often
# the UTC zero (0) hour time of the day when the leap second file
# is built.  It should be updated whenever a new IERS Bulletin C
# is issued.
#
#$     3755808000
#
# Leap second data have a lifetime.  Traditionally, this ends on
# the twenty-eighth (28) day of the month six months after the
# period of time described in the latest IERS Bulletin C.  This
# is the expiry time (#@).
#
#@     3786480000
#
# Leap second files have a hash, as define in NIST's FIPS 180
# Secure Hash Standard (SHS), current revision 4 (FIPS 180-4).
#
# FIPS Publications: <http://csrc.nist.gov/publications/fips/>
# Direct Link:       <http://dx.doi.org/10.6028/NIST.FIPS.180-4>
#
# It is based on an SHA[1] digest, created  using the data
# portions of the file including leap second data and the update
# and expiry timestamps.  All "white space" and comments are
# excluded in the computation thereof.  The 160-bit SHA[1]
# digest polynomial are encoded in five hexadecimal grouping at
# the end of the file (#h).  The hash itself is NOT included in
# the SHA[1].  It can also be calculated using GNU sha1sum which
# generates the same 160-bit digest, given the same data, in
# forty hexadecimal characters.
#
#   NTP       delta
#timestamp      T   sign      Date of Change

2272060800    10  # + : 1 Jan 1972 (MJD 41317)
2287785600    11  # + : 1 Jul 1972 (MJD 41499)
2303683200    12  # + : 1 Jan 1973 (MJD 41683)
2335219200    13  # + : 1 Jan 1974 (MJD 42048)
2366755200    14  # + : 1 Jan 1975 (MJD 42413)
2398291200    15  # + : 1 Jan 1976 (MJD 42778)
2429913600    16  # + : 1 Jan 1977 (MJD 43144)
2461449600    17  # + : 1 Jan 1978 (MJD 43509)
2492985600    18  # + : 1 Jan 1979 (MJD 43874)
2524521600    19  # + : 1 Jan 1980 (MJD 44239)
2571782400    20  # + : 1 Jul 1981 (MJD 44786)
2603318400    21  # + : 1 Jul 1982 (MJD 45151)
2634854400    22  # + : 1 Jul 1983 (MJD 45516)
2698012800    23  # + : 1 Jul 1985 (MJD 46247)
2776982400    24  # + : 1 Jan 1988 (MJD 47161)
2840140800    25  # + : 1 Jan 1990 (MJD 47892)
2871676800    26  # + : 1 Jan 1991 (MJD 48257)
2918937600    27  # + : 1 Jul 1992 (MJD 48804)
2950473600    28  # + : 1 Jul 1993 (MJD 49169)
2982009600    29  # + : 1 Jul 1994 (MJD 49534)
3029443200    30  # + : 1 Jan 1996 (MJD 50083)
3076704000    31  # + : 1 Jul 1997 (MJD 50630)
3124137600    32  # + : 1 Jan 1999 (MJD 51179)
3345062400    33  # + : 1 Jan 2006 (MJD 53736)
3439756800    34  # + : 1 Jan 2009 (MJD 54832)
3550089600    35  # + : 1 Jul 2012 (MJD 56109)
3644697600    36  # + : 1 Jul 2015 (MJD 57204)
3692217600    37  # + : 1 Jan 2017 (MJD 57754)
#
#h     ffee5390 2e3cf253 e15b646e 01768a18 e83785c3