Rapatronic camera
The Rapatronic camera is a high-speed camera with an exposure time of just 10 nanoseconds (billionths of a second).
The camera was developed by Harold Edgerton in the 1940s. The goal was to capture the rapidly expanding fireball from a nuclear explosion as part of the American nuclear test program.
The unusually short exposure time was achieved by avoiding a conventional mechanical shutter release. Instead, an electronic trigger mechanism consisting of a Kerr cell and two polarization filters was used in the Rapatronic camera . The two polarization filters are rotated by 90 ° and block the incident light. The Kerr cell sits between the two filters and can rotate the polarization plane of the light by applying a voltage. With a voltage pulse on the Kerr cell, the system acts as a trigger, the length of the voltage pulse controls the exposure time.
In order to receive film sequences of the first moments of a nuclear explosion, up to twelve cameras with different release delays were used next to one another.
The Rapatronic camera was equipped with a powerful telephoto lens (Tele-Rapatronic) for detailed shots of the very first moments of explosion inside the cabin on the bomb tower .
