Rapatronic camera

The Rapatronic Camera is a high-speed camera with an exposure time of only 10 nanoseconds ( billionths of a second).

The camera was developed by Harold Edgerton in the 1940s. The objective was to accommodate the rapidly expanding fireball of a nuclear explosion under the U.S. nuclear testing program.

The unusually short exposure time was achieved by the avoidance of a conventional mechanical shutter. Instead occurred in the Rapatronic camera, an electronic trigger mechanism consisting of a Kerr cell and two polarizing filters are used. The two polarization filters are rotated 90 ° and arranged to block the incident light. The Kerr cell is located between the two filters and can rotate by applying a voltage, the polarization plane of the light. By a voltage pulse on the Kerr cell, the system thus functions as a trigger, the length of the voltage pulses controls the exposure time.

To obtain film sequences of the first moments of a nuclear explosion, were up to twelve cameras with different tripping delay used side by side.

For detailed pictures of the very first moment explosions still inside the cabin on the bomb tower Rapatronic the camera was fitted with a telephoto lens ( telephoto Rapatronic ).