Piaget 580P, Быстрый старт

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En
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580P | 584P
Explanation of the functions
580P | 584P
Explanation of the functions
The moon-phases indicators
Watches with moon-phases indicators depict the cycle of the moon (new moon, first quarter, full moon,
last quarter) on their dials.
as the moon orbits the Earth, the relative positions of the sun, Earth and moon change constantly. The
phases of the moon correspond to the illuminated half of the moon being visible from different angles;
they are therefore not due to the shadow cast by the Earth on the moon. The moon merely reflects the
light of the sun on the Earth.
The phases of the moon depend on the relative positions of the sun, moon and Earth. The moon is full
when the sun and moon are on either side of the Earth. However they become invisible (new moon)
when they are both aligned on the same side of the Earth.
The first lunar phase is the newmoon. The main feature of this phase is the invisibility of the moon in
the sky. at this precise moment, the moon is located between the sun and the Earth.
Little by little, the illuminated side of the moon becomes visible to the human eye as it moves around
the Earth. at first, a slim crescent can be observed in the evening sky and, as the days pass, the crescent
becomes thicker and remains visible for increasingly longer periods of time. after the full moon, the
visible part of the moon diminishes.
a complete cycle is called a lunation, or lunar month, and corresponds to the duration between two
full moons (synodic period). it lasts 29 days, 12 hours, 44 minutes and 2.8 seconds, or approximately
29.530588 days.
The Piaget moon phase is said to be “astronomical”. The wheel that indicates the moon has 135 teeth.
With this system, the precision of the lunar month is 29 days, 12 hours and 45 minutes (29.53125 days
as opposed to 29.5 days in general). The gap between this mechanism and the true lunar cycle thus only
amounts to one day every 122 years (instead of one day every 3 years in general). The complication is
modelled on the northern hemisphere.
15 th night 11 th night
7
th night 4 th night night 0
29 th night 26 th night 22 nd night 18 th night
Sun
Earth
Gibbous moon
First quarter
(quadrature)
First crescent
new moon
(conjunction)
Last crescent
Last quarter
(quadrature)
Gibbous moon
Full moon
(opposition
)
The complication is symbolized by a disc bearing the moons and rotating according to the lunar
calendar. The dial reveals the shiny part of the moon, which illustrates the interplay between the sun
and the Earth perfectly.