Campbell-Stokes sunshine recorder

A Campbell-Stokes sunshine recorder is an instrument used to measure the amount of sunshine at a location. It consists of a glass sphere that concentrates sunlight onto a calibrated scale or card. When the sun is shining brightly, the focused light burns a trace or mark on the card. The length of the burned trace indicates the duration of sunshine each day. It provides a simple way to record sunny periods accurately over time, helping meteorologists understand climate patterns and solar exposure without the need for complex electronics.