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An approximately 4,000-year lunar calendar
Living in pace with the rotational movements
of the earth, the moon and the cosmos, no oth-
er instrument for measuring time was more
suited to reflecting with the greatest accuracy
the lunar circle in the firmament. This function
adorns certain Atmos® clocks.
A conventional quartz clock with moon phase
indication stays thoroughly accurate for two or
three years. The most highly perfected mechan-
ical watches, a field in which Jaeger-LeCoultre
excels, deviate by one day in 122 years; the
Atmos® clock, for its part, is designed to dis-
play the moon phases with exceptional accura-
cy for more than 4,000 years.
On the Atmos® clock, the moon phases are indi-
cated according to the real phases of the lunar
month, called the synodic period, corresponding
to the time elapsing between two full moons. For
the moon seen from the earth to have the same
position relative to the sun, it will have to travel
a further distance on its orbit. As a result, the
lunar month lasts slightly longer than the side-
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