HERCULES will use the same 10-meter reflector with an array of 193 phototubes.
Unlike HERCULES and existing detectors that consist or arrays of phototubes with overlapping fields of view, this detector would consist of two small telescopes with apertures of 10 or 20 centimeters set far apart so that their fields of view do not overlap.
It utilizes traditional optical components--a grating for dispersing the light from the sample; exit slits to select the exact light or element desired; and phototubes
to detect the amount of light present.
In early 1940, Arnold Beckman and his colleagues recognized that the DC amplifier designed for the pH meter could also be used with vacuum-type phototubes
An array of more than 100 small phototubes
, each of which acts as an independent picture element, provides 1/4 [degrees] resolution.