Definition of actinograph in English:

actinograph

noun

  • 1An instrument for recording variations in the intensity of solar radiation.

  • 2historical Photography
    Photography. A form of calculator for estimating the actinic power of daylight, to aid in determining an appropriate exposure. Now historical.

Origin

Mid 19th century; earliest use found in John Herschel (1792–1871), mathematician and astronomer. From actino- + -graph.

Pronunciation:

actinograph

/akˈtɪnəɡrɑːf//akˈtɪnəɡraf/