In the study of metal‐high explosive detonation wave interaction, by the pin technique, it is desirable to obtain time measurements to an accuracy of less than 1 m&mgr;sec over a total time interval of 5 &mgr;sec. Commercial instruments capable of a high degree of time resolution were not available and a special instrument was developed for this purpose. A cathode‐ray oscilloscope, displaying deflection type event pulses, is converted into a precise time‐measuring instrument by a calibrated zig‐zag sweep. The record is obtained by single‐shot photography of the cathode‐ray tube sweep which is triggered by the event to be measured. The calibrated zig‐zag sweep is crystal controlled at 2 Mc and has superimposed deflection type time marks, 2 m&mgr;sec wide, at 50‐m&mgr;sec interval, synchronized with the zig‐zag frequency. The apparatus can drive six oscilloscopes simultaneously or in sequence from delayed triggers.