Introduction
Although passive night vision technology capable of allowing vision under ambient starlight conditions has existed since the 1950s, it was not until the AN/PVS-4 was developed that a practical, high quality device that met military requirements was first made available.
Unlike earlier passive starlight weaponscopes the AN/PVS-4 provided a high quality image without significant distortion, could adjust to changing ambient light conditions, was able to take multiple reticles to operate in many roles and had protective features allowing it to shut down in the event of exposure to bright light, but still recover in time after a muzzle flash for the operator to see the round hit the target.
Using the MX-9644 Image Intensifier tube the AN/PVS-4 became one of the most widely used night vision scopes and has been in active use for more than a quarter of a century.
Read more about this topic: AN/PVS-4
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