The History of Timekeeping

Sundial

Clepsydra

Astrolabe

Candle Clock

Sandglass

Mechanical Clock

Spring-Driven Clock

Pendulum Clock

Quartz Clock

Cesium Atomic Clock

 

Astrolabe
  The astrolabe was believed to have been invented in the 2nd century A.D by Ptortemy. He was riding along on his donkey with a a celestial globe. He dropped it on the ground making it a 2-D celestial sphere. The astrolabe, also known as the “star grasper”, is a combination of movable plates. The rete and the tympan are the most significant of those. The rete shows the movements of the sun and the tympan shows the coordinates of the celestial sphere. The alidade and the rule, other parts of the astrolabe distinguished the altitudes of the stars. These devices were able to find location, distance, and of course, time. The astrolabe’s design is based on the map that was created in 150 BC by a Greek astronomer named Hipparchus. On this map, stars appeared in a perpendicular line all connected to a designated point on the plane. This map displayed where the stars were placed in relation to the Earth’s equator. However, for centuries this device was unable to accurately measure time. They also never became very popular due to the belief by some Christians that it was a tool of the devil. However, later it did play a key role in more accurate timekeeping devices such as the advancement of the sundial.