--- australasia | 36 +++++++++++++++--------------------- 1 file changed, 15 insertions(+), 21 deletions(-) diff --git a/australasia b/australasia index 749b72c8..84d94b99 100644 --- a/australasia +++ b/australasia @@ -2199,24 +2199,18 @@ Zone Pacific/Efate 11:13:16 - LMT 1912 Jan 13 # Vila # an international standard, there are some places on the high seas where the # correct date is ambiguous. -# From Wikipedia <https://en.wikipedia.org/wiki/Time_zone> (2005-08-31): -# Before 1920, all ships kept local apparent time on the high seas by setting -# their clocks at night or at the morning sight so that, given the ship's -# speed and direction, it would be 12 o'clock when the Sun crossed the ship's -# meridian (12 o'clock = local apparent noon). During 1917, at the -# Anglo-French Conference on Time-keeping at Sea, it was recommended that all -# ships, both military and civilian, should adopt hourly standard time zones -# on the high seas. Whenever a ship was within the territorial waters of any -# nation it would use that nation's standard time. The captain was permitted -# to change his ship's clocks at a time of his choice following his ship's -# entry into another zone time - he often chose midnight. These zones were -# adopted by all major fleets between 1920 and 1925 but not by many -# independent merchant ships until World War II. - -# From Paul Eggert, using references suggested by Oscar van Vlijmen -# (2005-03-20): -# -# The American Practical Navigator (2002) -# http://pollux.nss.nima.mil/pubs/pubs_j_apn_sections.html?rid=187 -# talks only about the 180-degree meridian with respect to ships in -# international waters; it ignores the international date line. +# From Wikipedia <https://en.wikipedia.org/wiki/Nautical_time> (2023-01-23): +# The nautical time zone system is analogous to the terrestrial time zone +# system for use on high seas. Under the system time changes are required for +# changes of longitude in one-hour steps. The one-hour step corresponds to a +# time zone width of 15° longitude. The 15° gore that is offset from GMT or +# UT1 (not UTC) by twelve hours is bisected by the nautical date line into two +# 7°30' gores that differ from GMT by ±12 hours. A nautical date line is +# implied but not explicitly drawn on time zone maps. It follows the 180th +# meridian except where it is interrupted by territorial waters adjacent to +# land, forming gaps: it is a pole-to-pole dashed line. + +# From Paul Eggert (2023-01-23): +# The American Practical Navigator <https://msi.nga.mil/Publications/APN>, +# 2019 edition, merely says that the International Date Line +# "coincides with the 180th meridian over most of its length." -- 2.37.2