Gnomonics: Measurement of Shadows and Solar Time

This lecture introduces gnomonics, the science of measuring time using shadows. It covers the concept of equinoxes and solstices, the role of the gnomon in determining time, and the relationship between the shadow length and the latitude of a place. The transition from astronomy to gnomonics is explained, along with the significance of the meridian line. Various astronomical planes and axes are discussed, including the celestial equator and the Earth's polar axis. The lecture also delves into the practical applications of gnomonics in determining solar time and the variations in shadow length throughout the year.