--- leap-seconds.list | 66 ++++++++++++++++++++++++++++--------------------------- 1 file changed, 34 insertions(+), 32 deletions(-) diff --git a/leap-seconds.list b/leap-seconds.list index 7df3de6..607fa7d 100644 --- a/leap-seconds.list +++ b/leap-seconds.list @@ -15,12 +15,17 @@ # are transmitted by almost all time services. # # The first column shows an epoch as a number of seconds -# since 1900.0 and the second column shows the number of -# seconds that must be added to UTC to compute TAI for -# any timestamp at or after that epoch. The value on -# each line is valid from the indicated initial instant -# until the epoch given on the next one or indefinitely -# into the future if there is no next line. +# since 1 January 1900, 00:00:00 (1900.0 is also used to +# indicate the same epoch.) Both of these time stamp formats +# ignore the complexities of the time scales that were +# used before the current definition of UTC at the start +# of 1972. (See note 3 below.) +# The second column shows the number of seconds that +# must be added to UTC to compute TAI for any timestamp +# at or after that epoch. The value on each line is +# valid from the indicated initial instant until the +# epoch given on the next one or indefinitely into the +# future if there is no next line. # (The comment on each line shows the representation of # the corresponding initial epoch in the usual # day-month-year format. The epoch always begins at @@ -44,9 +49,9 @@ # by the International Bureau of Weights and Measures # (BIPM). See www.bipm.fr for more information. # -# 3. The current defintion of the relationship between UTC +# 3. The current definition of the relationship between UTC # and TAI dates from 1 January 1972. A number of different -# time scales were in use before than epoch, and it can be +# time scales were in use before that epoch, and it can be # quite difficult to compute precise timestamps and time # intervals in those "prehistoric" days. For more information, # consult: @@ -59,16 +64,11 @@ # July, 1991. # # 4. The insertion of leap seconds into UTC is currently the -# responsibility of the International Earth Rotation Service, -# which is located at the Paris Observatory: -# -# Central Bureau of IERS -# 61, Avenue de l'Observatoire -# 75014 Paris, France. +# responsibility of the International Earth Rotation Service. # # Leap seconds are announced by the IERS in its Bulletin C # -# See hpiers.obspm.fr or www.iers.org for more details. +# See www.iers.org for more details. # # All national laboratories and timing centers use the # data from the BIPM and the IERS to construct their @@ -126,7 +126,7 @@ # Time and Frequency Division # NIST # Boulder, Colorado -# jlevine@boulder.nist.gov +# Judah.Levine@nist.gov # # Last Update of leap second values: 11 January 2012 # @@ -139,18 +139,19 @@ #$ 3535228800 # # The NTP timestamps are in units of seconds since the NTP epoch, -# which is 1900.0. The Modified Julian Day number corresponding -# to the NTP time stamp, X, can be computed as +# which is 1 January 1900, 00:00:00. The Modified Julian Day number +# corresponding to the NTP time stamp, X, can be computed as # # X/86400 + 15020 # # where the first term converts seconds to days and the second -# term adds the MJD corresponding to 1900.0. The integer portion -# of the result is the integer MJD for that day, and any remainder -# is the time of day, expressed as the fraction of the day since 0 -# hours UTC. The conversion from day fraction to seconds or to -# hours, minutes, and seconds may involve rounding or truncation, -# depending on the method used in the computation. +# term adds the MJD corresponding to the time origin defined above. +# The integer portion of the result is the integer MJD for that +# day, and any remainder is the time of day, expressed as the +# fraction of the day since 0 hours UTC. The conversion from day +# fraction to seconds or to hours, minutes, and seconds may involve +# rounding or truncation, depending on the method used in the +# computation. # # The data in this file will be updated periodically as new leap # seconds are announced. In addition to being entered on the line @@ -163,10 +164,11 @@ # is announced. # # The following entry specifies the expiration date of the data -# in this file in units of seconds since 1900.0. This expiration date -# will be changed at least twice per year whether or not a new leap -# second is announced. These semi-annual changes will be made no -# later than 1 June and 1 December of each year to indicate what +# in this file in units of seconds since the origin at the instant +# 1 January 1900, 00:00:00. This expiration date will be changed +# at least twice per year whether or not a new leap second is +# announced. These semi-annual changes will be made no later +# than 1 June and 1 December of each year to indicate what # action (if any) is to be taken on 30 June and 31 December, # respectively. (These are the customary effective dates for new # leap seconds.) This expiration date will be identified by a @@ -182,10 +184,10 @@ # current -- the update time stamp, the data and the name of the file # will not change. # -# Updated through IERS Bulletin C46 -# File expires on: 28 June 2014 +# Updated through IERS Bulletin C47 +# File expires on: 28 December 2014 # -#@ 3612902400 +#@ 3628713600 # 2272060800 10 # 1 Jan 1972 2287785600 11 # 1 Jul 1972 @@ -228,4 +230,4 @@ # the hash line is also ignored in the # computation. # -#h 1151a8f e85a5069 9000fcdb 3d5e5365 1d505b37 +#h 9195bac3 a050810e e85fc815 e752446a 76ade206 -- 1.9.1