photochronograph

Pho`to`chron´o`graph

n.	1.	(Physics) An instrument for recording minute intervals of time. The record is made by the power of a magnetic field, due to an electric signaling current, to turn the plane of polarization of light. A flash, coinciding in time and duration with the signal, is thus produced and is photographed on a moving plate.
	2.	(Astron.) An instrument for the photographic recording of star transits.

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photochronograph

1. a camera for recording motion by a series of photographs taken at brief intervals.
2. the photograph so produced.
3. a camera that records the exact time of the event it is photographing by exposing a moving sensitized plate to the tracing of a thin beam of light synchronized with the event.

See also: Photography, Time