You searched for: “actinograph
actinograph (s) (noun), actinographs (pl)
An instrument for recording the variations in the power of the solar rays: The actinograph was invented by Sir J. Herschel in 1838.

An actinograph is one of the various devices used for recording the actinic power of light and for determining the correct time of exposure for photographic plates.

The seldom used terms "radiograph" and "radiography" mean that images are produced on film or on another sensitive surface by radiation, such as X-rays or gamma rays passing through an object.