Night Vision Devices are electronically enhanced optical devices that enable us to see in near-total darkness. Even on a moonless night or in a dark interior, see everything within range of the IR illuminator.
Though Night Visions Devices (NVD's) are very easy to use, technical jargon makes their literature tricky to understand. While any night vision equipment will greatly improve your ability to see at night, there are different grades of night vision goggles, night vision scopes, and thermal imaging cameras - from simple Gen 1 Night Vision monocular to an advanced Generation 3 Military Night vision goggles and rifle scopes - that will give you different levels of performance. While various digital night vision systems and thermal imaging cameras are becoming more available, the information about Night Vision presented below mostly focuses on how the most common night vision technology works - NV devices with various types of image intensifiers that convert weak light from the visible and near-infrared spectrum to visible light detectible by a human eye.
How Night Vision Works
Night Vision Scopes are sophisticated optico-electronic devices that assist viewing in near or complete darkness by amplifying all available light. Unlike telescopes and binoculars, night vision is usually not intended for magnification of remote objects (most night vision devices offer either no magnification 1x to very low 2x to 4x magnification).
Most night vision devices offered by OpticsPlanet.com include a built-in Infra Red (IR) Illuminator that acts as a "night vision flashlight" and provides additional light, making viewing in complete darkness a reality. A small red dot appears on the front of the night vision device when the IR Illuminator is ON. There are now Night Vision Blackout Infrared IR Filter Kits for Military Vehicles and even regular Spot Light Flashlights.
Choosing a Night Vision Device
The most common question in regards to night vision selection is "What is the difference between night vision generations?" All Night Vision products amplify existing light, allowing you to see in dark conditions too dark for the naked eye. Night Vision goggles, monoculars and binoculars collect and amplify existing light through the objective lens, which is then focused on the image intensifier. Inside the intensifier, a photocathode is "excited" by the light and converts the photon energy into electrons. These electrons accelerate across an electrostatic field inside the intensifier and strike a phosphor screen (like a green monochrome TV screen) which emits an image that you can see. It is the acceleration of electrons, which provides gain and enhances the image. The key difference between the night vision generations is the intensifier technology. Gen. I Night Vision devices use an intensifier tube that amplifies ambient light by accelerating electrons and striking a phosphor surface just like a Television. Generation II night vision devices add a micro-channel plate that multiplies the number of electrons before they impinge on the phosphor screen, thus increasing gain. Generation III Night Vision goggles, monoculars and scopes further add a Gallium Arsenide photocathode which creates significantly more photoelectrons than Gen II night vision devices. Generation 4 Night Vision is now offered by ATN. Generation II and III night vision devices offer greater light amplification, they are definitely better than Generation I, but a price beyond the reach of most buyers. Modern Generation I Night Vision devices are high quality and provide light amplification adequate for most recreational activities camping, hiking, fishing, boating, and nature viewing, and for many professional uses such as surveillance, search and rescue, and property management.
What Night Vision to Buy
When you are looking for night vision goggles or binoculars, choose the optical lens package, unit size and price that suits you best, and for most recreational use you normally do not worry about the slight differences in technical specifications. So many variables affect seeing in the dark. Some environments just soak up the light, particularly trees and dense vegetation. It is not possible to give exact, reliable performance specifications that will fit real life conditions. We can only list the technical capabilities. If you want to read up on technical details and see more details on technical details of image intensifier tubes used in night vision devices, please read our "HOW STARLIGHT TECHNOLOGY WORKS" article provided by ATN Night Vision (ATNcorp.com).
Refer to the GLOSSARY for definitions of terms.