A four-stage electro-magnetically focused photocathode image intensifier, of the type used by astronomers during the 1970s-80s.

This type of instrument was used in conjunction with major instruments such as the 2.5-metre Isaac Newton Telescope (INT) and the Anglo-Australian Telescope (AAT) to measure the separation within binary star systems.

The tube consisted of a vacuum containing a high-voltage photocathode and a phosphor screen. As the incoming photons of light struck the photocathode, they generated a shower of electrons. These particles continued along the tube and hit the phosphor screen, creating even more electrons. This cascade effect amplified the signal to enable astronomers to view the image on a television screen at a greater resolution and light sensitivity.

Manufacturer's label: Type 9912 (SU), no.1372.

This particular image intensifier was never used, it is as new.