Antique Sundial Clocks

A sundial is a device that measures time by the position of the Sun. The most commonly seen designs, such as the 'ordinary' or standard garden sundial, cast a shadow on a flat surface marked with the hours of the day. As the position of the sun changes, the time indicated by the shadow changes. However, sundials can be designed for any surface where a fixed object casts a predictable shadow.

Most sundial designs indicate apparent solar time. Minor design variations can measure standard and daylight saving time, as well.

Sundials in the form of obelisks (3500 BC) and shadow clocks (1500 BC) are known from ancient Egypt, and were developed further by other cultures, including the Chinese, Greek[1], and Roman cultures. A type of sundial without a gnomon is described in the Old Testament (Isaiah 38:8).(ca.700 BC).

The mathematician and astronomer Theodosius of Bithynia (ca. 160 BC-ca. 100 BC) is said to have invented a universal sundial that could be used anywhere on Earth. The French astronomer Oronce Finé constructed a sundial of ivory in 1524. The Italian astronomer Giovanni Padovani published a treatise on the sundial in 1570, in which he included instructions for the manufacture and laying out of mural (vertical) and horizontal sundials. Giuseppe Biancani's Constructio instrumenti ad horologia solaria (ca. 1620) discusses how to make a perfect sundial, with accompanying illustrations.

The oldest sundial in Britain is incorporated into the famous Bewcastle Cross. The dial is divided into four tides, covering the parts of the working day in medieval times.

This device is commonly used in the modern world because of convience and practicality.