Measuring times to determine positions

TL;DR

This paper explores how ancient devices like sundials and water-clocks measure time and determine geographic positions, highlighting their historical significance and the principles behind their operation.

Contribution

It analyzes the methods by which sundials can be used to find latitude and north-south direction, and briefly discusses the problem of longitude determination.

Findings

Sundials can be used to determine latitude based on shadow angles.

The orientation of sundials helps identify north-south direction.

The paper provides historical context on ancient time-measuring devices.

Abstract

Among the first devices used to measure the time we find the sundials and the water-clocks, as told by Vitruvius in his book on the Architecture. The sundials work because of the shadows cast by a rod or pole, the gnomon, on their basements. Besides being an instrument able to measure the time intervals, the sundial provided information on Earth and heaven to the ancient astronomers. Here we discuss how this device is able to determine the latitude and the north-south direction. The problem of the longitude is also shortly discussed.