Night vision devices need some sort of light source in order to operate. The equipment makes use of small amounts of natural lighting, such as moonlight and starlight. That minuscule amount of light is utilized by converting the light’s energy (photons) into electrical energy, or electrons.
The electrons pass through a small disc inside the night vision device that contains millions of individual channels. As the light makes it’s way through the channels thousands of new electrons are released (multiplied). This new, larger amount of electrons then bounce off a phosphor screen (the greenish glow associated with night vision) that instantly converts the electrons back to photons. This conversion of amplified electrical energy back into light energy (remember, the energy has been greatly amplified at this point) allows the user to see “in the dark.”
Night vision binoculars vary in price. The device above comes in just under $8,000.
Beacons, such as the Phoenix Jr. (above) are used to help prevent friendly-fire accidents. The tiny flashing infrared light can only be seen using night vision (see top image).
A GPS equipped Phoenix Intruder Tripwire Beacon is placed along a pathway traveled by a potential suspect, or other target (military use). The beacon emits a signal that’s both visible and traceable (GPS). For military use mortars may be sent to the beacon’s location, eliminating the target. Police surveillance and apprehension teams would track, locate, and engage their suspect. Then they’d take him into custody.
– Night vision does not show normal depth perception.
– Objects with dull surfaces that appear light during the day show up dark at night when viewing with night vision. And, objects that appear dark during the day, but have shiny surfaces, will appear lighter at night when seen with night vision.
– Bright ambient light reduces the images seen through night vision devices. Therefore, reflective light, such as light that’s amplified by rain, fog, mist, etc. hinders the performance of night vision devices.