c. 3500 BC, a gnomon in China dated 2300 BC, and an Egyptian sundial dated 1500 BC are some of the earliest methods for measuring the sun's position.

Babylonian astronomers knew that the hours of daylight varied throughout the year. A tablet from 649 BC shows that they used a 2:1 ratio for the longest day to the shortest day, and estimated the variation using a linear zigzag function. It is not clear if they knew of the variation in the