Audemars Piguet Royal Oak Concept GMT Tourbillon Instructions for use manual - page 7
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Introduction
tIMES-zONES
The earTh’s roTaTion means ThaT True
local Time changes aT The leasT moVemenT
To The easT or wesT.
A worldwide system of meridians at 15° intervals
has therefore been adopted to measure the average
local time. The earth has thus been divided into
24 time zones, with the central meridian in the
middle.
This system was adopted during the international
conference in washington in 1884 and greenwich
was chosen as the earth’s prime meridian. The
meridian passing through greenwich in great
britain was chosen as the prime meridian, i.e. the
reference axis for coordinated universal Time
(uTc or gMT) on which all time zones would be
based.
Thus you have to put your watch forward by one
hour when crossing from one time zone to the next
going east. Put your watch back by one hour when
crossing from one time zone to the next going west.
Theoretically, all of the points on the globe with
the same longitude should be in the same time
zone. in reality, each country has defined its time
zone(s) as a function of political borders, among
other considerations (see the map of time zones
based on political borders).
Time zones follow political borders
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