The apparatus comprises one or more light sources (18,15) for providing
light emitted from or reflected by the moving article and one or more light sensing
mechanisms (15, 12, 50, 51) arranged to provide a signal when illuminated
by said light, at least one of the light sensing mechanisms (15, 12, 50, 51)
being arranged to detect when the moving article intercepts a known detection plane
(19, 20, 21, 64, 65, 66, 67), wherever the article intercepts the plane.
The sensing mechanism may comprise a slit aperture (10, 11, 12, 23, 60, 61)
and/or cylindrical lens to define a detection plane. The apparatus may be used
to measure the pre-impact and post-impact position and/or motion of a golf clubhead
(7) and/or of a golf ball (1) during execution of a golf shot.
