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SRDE was responsible for carrying out the research and development necessary to provide the Army with the means to pursue its normal fighting activities during the hours of darkness. These included the surveillance of enemy troop movements, driving all kinds of vehicles and missile guidance on to acquired targets at night.

diode image converter was developed that produced a visible image from the photons invisible to the human eye, emitted from a scene illuminated by an infra-red source of light. A range of active night viewing devices were developed based on this image converting device. Because the sources used for flooding the scene with infra-red radiation were easily detected, the development of passive viewing systems with a sensitivity to respond to the night sky radiation was initiated.


A starting point for this work was the demonstration in SRDE in 1956 that the starlight energy reflected from the night scene was sufficient to create an electron signal from a sensitive photoemissive cathode of high enough signal-to-noise ratio to warrant the feasibility of eventually converting the signal to a visible output that could be utilised by the human eye. Extensive studies of the radiation from the night sky were carried out to quantify its temporal and spatial variations.

To aid the research and development programme a 100-metre long dark tunnel was constructed at Steamer Point in which lighting could be controlled to simulate various night-time illumination levels.

In addition to in-house studies, work was sponsored in industry, where the considerable expertise of MULLARD LTD at their RESEARCH LABS. and RADIO VALVE COMPANY proved invaluable for the production of prototype active and passive viewers for evaluation and the subsequent manufacture of night viewing equipment that satisfied the stated requirements of the military user.

Projects in the Work Programme included:

  • Intensity And Spectral Range Of The Night Sky Radiation

  • First Generation Passive Viewers

  • Second Generation Passive Viewers

  • Third Generation Passive Viewers

  • Nightime Infrared Radiation

  • Illumination By A Pulsed Light Source

  • A Gated Viewer For Target Recognition In Adverse Atmospheric Conditions

  • Srde Engineered Image-Intensifier Viewing Systems

  • Measurements Of Important Variables Of The Night Sky

  • Image Sensor Based On A Silicon Mosaic For Night Viewing

  • Engineering Aspects Of Night Vision Systems

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