Abstract: A shutter assembly includes a base plate defining a shutter opening having a central axis, and a drive assembly coupled to the base plate. The drive assembly includes a rotatable pinion gear, and a drive rack mating with the pinion gear and moveable in a substantially linear direction in response to rotation of the pinion gear. The shutter assembly also includes a plurality of shutter blades operably connected to the drive rack. The plurality of shutter blades are configured to rotate between an open position exposing the shutter opening and a closed position substantially occluding the shutter opening in response to movement of the drive rack in the substantially linear direction.

Abstract: A variable ramp voltage generated by a first 555 timer is applied to the control electrode of a second 555 timer for controllably varying the delay function of the second timer. The second timer is triggered in accordance with the motion to be observed, several trigger signals being applied during each ramp. The output signals from the second timer are thus timed at progressively longer intervals from the respective input signals during each ramp. The output signals are applied to trigger a stroboscope, producing a cinematographic slow motion view of a selected portion of the motion under observation.