Definitions

1. noun

An instrument used to record the direction and intensity of solar radiation, typically on a ship.

“The sailors used the actinograph to measure the sun’s radiation and adjust their navigation accordingly.”

2. noun

A device that records the direction and amount of solar radiation on a graph, used in meteorology and astronomy.

“The actinograph in the laboratory helped scientists study the patterns of solar radiation and its effects on the Earth’s climate.”