Zenith EL PRIMERO series, Operating Instructions Manual

Page: 63 / 89

EQUATION
OF TIME*
THE CLOSEST TO THE TRUE PASSING OF TIME.
WHO REFLECTS, WHEN CONSULTING ONE'S
WATCH, THAT THE TIME SHOWN IS MERELY
A CONVENTION?
It is only for convenience's sake that the length
of a day was definitively set at 24 hours. In fact, its
actual length varies constantly. The oval shape of
the Earth's orbit and the angle of its axis cause a
drift that varies from up to 16 minutes ahead of or
14 minutes behind conventional time compared to
the time shown on a sun dial. In very literal terms,
if your watch were to have an appointment with
the sun every day at the precise moment its hands
indicated noon, it would observe the sun arriving
either early or late depending on the day of the
year, with a potential difference of up to a quarter
of an hour. In fact, there are only four days of the
year on which the two times match up exactly.
Zenith has equipped its most daring model, the
Christophe Colomb, with a function that indicates
the 'equation of time' – the difference between the
travel of the hands and the sun.
* Depending on the model
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