Eagle3
07-21-04, 08:33 AM
A very interesting article on the history and development of NVG's (Night Vision Googles)
Seeing in the dark was once the province of owls and other night creatures, or Vin Diesel's Riddick -- but with improved technology, Soldiers are masters of the night.
Up until only recently, fighting at night was something that was done only at great risk -- and not just because of "things that go bump in the night." Prior to the development of effective battlefield illumination (in the form of magnesium parachute flares), the only light available was that provided by the moon and stars -- not necessarily what you need to distinguish friend from foe.
On the other hand, while white light illumination (visible spectrum) provides enough light to allow combatants to engage in night operations, it has the disadvantage of giving away your position and intentions -- there is no disguising the fact that a 250,000 candlepower magnesium flare is burning in the sky above you. While this isn't necessarily an issue in a defensive situation (if you are under attack, the enemy obviously knows where you are), it is a limiting factor in conducting offensive operations; once you deployed illum, both friend and foe alike knew where the action was taking place.
To get around this limitation, a means was needed to enable soldiers to see and fight at night without depending on the all revealing white light -- enter Night Vision. Used properly, night vision equipment allows you to detect a person standing over 200 yards (183 m) away on a pitch-black night. Owls would be jealous of that sensitivity.
How It Works
Night Vision Devices (NVDs) are electrically powered image enhancing devices which use an image enhancing tube to convert a low light photo-image into an electronic one, and then back into an enhanced photo-electric image. The process by which this is accomplished is fairly straightforward. The low-light image (made up of reflected visible and near infrared photons) is first captured by the objective lens and then focused into the image intensifier tube. On the objective side of the tube is a photo cathode that converts the photons striking it into electrons. These electrons, accelerated and multiplied by an energized anode inside the tube, move down the tube until they strike a phosphor screen at the far end of the tube. The phosphors, once energized by the electron's electrical charge, emit green photons that are passed through the ocular lens at the rear of the tube, which is used by the device operator to magnify and focus the image.
More (http://www.military.com/soldiertech/0,14632,Soldiertech_NightVision,,00.html?ESRC=navy .nl)
Seeing in the dark was once the province of owls and other night creatures, or Vin Diesel's Riddick -- but with improved technology, Soldiers are masters of the night.
Up until only recently, fighting at night was something that was done only at great risk -- and not just because of "things that go bump in the night." Prior to the development of effective battlefield illumination (in the form of magnesium parachute flares), the only light available was that provided by the moon and stars -- not necessarily what you need to distinguish friend from foe.
On the other hand, while white light illumination (visible spectrum) provides enough light to allow combatants to engage in night operations, it has the disadvantage of giving away your position and intentions -- there is no disguising the fact that a 250,000 candlepower magnesium flare is burning in the sky above you. While this isn't necessarily an issue in a defensive situation (if you are under attack, the enemy obviously knows where you are), it is a limiting factor in conducting offensive operations; once you deployed illum, both friend and foe alike knew where the action was taking place.
To get around this limitation, a means was needed to enable soldiers to see and fight at night without depending on the all revealing white light -- enter Night Vision. Used properly, night vision equipment allows you to detect a person standing over 200 yards (183 m) away on a pitch-black night. Owls would be jealous of that sensitivity.
How It Works
Night Vision Devices (NVDs) are electrically powered image enhancing devices which use an image enhancing tube to convert a low light photo-image into an electronic one, and then back into an enhanced photo-electric image. The process by which this is accomplished is fairly straightforward. The low-light image (made up of reflected visible and near infrared photons) is first captured by the objective lens and then focused into the image intensifier tube. On the objective side of the tube is a photo cathode that converts the photons striking it into electrons. These electrons, accelerated and multiplied by an energized anode inside the tube, move down the tube until they strike a phosphor screen at the far end of the tube. The phosphors, once energized by the electron's electrical charge, emit green photons that are passed through the ocular lens at the rear of the tube, which is used by the device operator to magnify and focus the image.
More (http://www.military.com/soldiertech/0,14632,Soldiertech_NightVision,,00.html?ESRC=navy .nl)