Meaning of photochronograph | Babel Free

Definitions

1. An instrument for recording very short 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. An instrument for the photographic recording of star transits.

CEFR level