This invention is an apparatus and method for determining the velocity of a
projectile. A light curtain unit (20) creates two light curtains (46)(48)
and two sensing planes (50)(52). The projectile causes light from
the light curtain (46)(48) to be reflected into the detectors (22a)
and (24a) of the sensing planes (50)(52). The time
for a projectile to pass through one sensing plane to the other is measured and
calculated for display by the Display Unit (10).