Letter from the Publisher

Human time is not the same as that of nature! The latter is intrinsically
variable and seems to delight in slowing down or accelerating the pace of
successive days. The inclined position of the Earth’s axis and its elliptical
path around the sun lead to irregular diurnal and nocturnal periods that vary
according to the time of year. Nonetheless, society has come to need fixed
temporal points of reference, which is why we initiated the convention of
mean time. The discrepancy between solar (or “natural” time) and civil,
standard (or “artificial”) time varies over the months and is known as
the equation of time. The year 2009, which was designated as the
Year of Astronomy by the United Nations Assembly, appears to have
sparked the renewal of astronomical horological functions, including the
launch of new wristwatches with so-called “running” equations of time.
They serve as eloquent reminders that time can never be truly disconnected
from the movement of the stars.
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