military@amdcad (04/04/91)
From: att!ihlpm!rats In <1991Apr4.042323.12456@amd.com> Robert Allen states: >In article <1991Apr3.024528.23814@amd.com> ssingh@watserv1.waterloo.edu writes: >>I was wondering if someone could explain to me how those devices >>used in the Gulf War allows soldiers to see in the dark. >I believe you are referring to the Starlight scopes. These use light >amplifying image tubes inside, which gather ambient light from stars, >the moon, etc., magnify it, and allow you to see in "the dark". The >starlight scope is completly passive. It can use infrared light from >an infrared flashlight or spotlight as well. Some image intensification night vision devices actually include a supplimental IR illuminator if there is insufficient light. The night vision goggles for example include this feature. >There are also infrared scopes, which require and active IR light source. >These scopes cannot see ambient light, Wrong, the S-1 photocathode (Ag-O-Cs) has usable sensitivity in the visible light spectrum, and was actually used in the earliest television camera tubes; these had to incorporate an IR filter to block IR radiation from studio incandescent lamps. I might be mistaken, but the IR sniperscope made for the M-14 rifle, utilising the 6914 infrared image convertor tube, had an accessory lens cap with a small opening that allowed it to used in daylight conditions. >and using them with a projector >will put you at a disadvantage if the enemy has starlight scopes, since >they will see your IR emitter, but you can't see anything of theirs. The Soviet SVD sniper rifle had a rifle scope that included a "metascope" capability to enable it to spot "enemy" IR emitters. This was in the form of a phosphor that you charged from an external visible light source within the scope. When an area was scanned with the scope that contained an IR emitter, the stored energy in the phosphor was released as visible light, exposing the location of the emitter. During WW II, some U.S. "metacopes" for IR detection utilised a phosphor that was powered by radium, thus obviating the need for external charging via visible light, but I digress...