Abstract: A microscope system for observing moving particles makes use of a television camera for producing a continuing series of images of such particles. A source of light pulses illuminate the particles with each pulse for a period short enough to stop their movement for the camera. The light source and camera are synchronized so that the light pulses occur only between times that the camera produces image-information signals. For obtaining particle size measurements, a single light pulse during a time that the camera is not producing image-information signals is sufficient. For obtaining paticle velocity measurements, two light pulses are required so that a "double exposure" occurs at the camera during a time that the camera is not producing image-information signals.