Dividing and measuring time as it passes – man has always
focussed on this by observing nature. Above all astronomical
events such as the movement of the sun and the different phases
of the moon are clearly identifiable thanks to their periodical
recurrence. From these our forefathers once developed the
calculating units for year, month, day and hour. The year with
its different seasons is calculated from the orbit of the earth
around the sun. The month corresponds with the movement of the
moon around the earth and the change in the phases of the moon.
The day results from the rotation of the earth around itself and
the consequent change of day and night. In the further course of
history the sun served to divide the day into hours and minutes.
In earliest times knowledge of the sky was necessary for people
in agricultural areas essential for survival. Later a fi rmer
understanding of time also served to allow people to determine
precisely their place in the sequence of generations or their
own age. To this da