A sequential flash for photographing trajectories of saltating particles

To obtain statistically useful samples of the maximum heights attained by saltating snow during drifting, several thousand particle trajectories must be measured. This paper describes the light source for photographs of sufficient quality that computer analysis can determine heights automatically. The method uses eight small electronic flash units fired in sequence through color filters, with the light focused through a single lens. Since the number. color and interval between flashes can be varied, the device could be used for other studies where object position or speed is of interest.