Night vision
Night vision is being able to see in the dark. Some animals, like cats, have natural night vision - they can see in very low light without any help. Humans do not have good night vision. If there is not enough light to see well, a human may need a night vision device such as night vision goggles to help them see.
Night vision goggles come in two types:
- Amplification - This increases the visible light, and makes it bright enough for our eyes to see. It works well outside but cannot be used in a completely dark place, such as a cave.
- Infrared - Uses a different part of the light that we cannot see. It sees heat energy. Animals and vehicles produce heat and are easily seen in infrared, even when it is completely black.
Night Vision Media
Two American soldiers pictured during the 2003 Iraq War seen through an image intensifier.
The electromagnetic spectrum, with the visible portion highlighted
Normalised absorption spectra of the three human photopsins and of human rhodopsin (dashed). Drawn after Bowmaker and Dartnall (1980).
1974 US Army film about the development of military night vision technology
USMC M3 Sniperscope assembled on a M1 Carbine. Introduced during the Korean War, it was an early active infrared night vision equipment powered by a large 12 volt battery that was carried in a rubberized canvas backpack.
An M60 tank with an infrared searchlight mounted on the cannon.
Binocular night vision goggles on a flight helmet. The green color of the objective lenses is the reflection of the light interference filters, not a glow.
