Although the image dissector was probably the first all-electronic optical scanning device to be used (Ref. 1) for generating a video television signal, its first reported use (Ref. 2) as an optical tracking device did not occur until 1960. Since that date it has enjoyed a steadily increasing popularity as a specialized optical scanning device, especially for tracking stars (Ref. 3) and laser (Ref. 4, 10) images.