The Art of Measuring Time

Prague Astronomical Clock (HERE)

For thousands of years, devices have been used to measure and keep track of time. The current sexagesimal system of time measurement dates to approximately 2000 BCE, in Sumer. 

Most of the first clocks were not so much chronometers as exhibitions of the pattern of the cosmos. Clearly the origins of the mechanical clock lie in a complex realm of monumental planetariums. 

The medieval Prague Astronomical Clock at left was installed in 1410 - more than 130 years before Copernicus published ‘On the Revolutions of the Celestial Spheres’ in 1543. It is the third-oldest astronomical clock in the world and the oldest one still working (HERE)