Night vision related issues

1. Since the night vision device can detect infrared light, can it detect heat?
A night vision device is an optical amplifier that operates in the "nearly visible" range of light, generally speaking, this range is in the 750-850 nm range. It cannot measure heat because the thermal frequency is much lower than the spectral frequency and requires thermal imaging.

2. What special design does the night vision device have?
All night vision goggles are designed to automatically power down when not in use, and only start to power up when the start switch is pressed. The binocular device has an "on/off" switch that requires the user to turn off the device after use. It is normal if there is a certain "humming" sound, it is intentionally designed to help the user distinguish between power on and power off. The image in the night vision device is formed by a phosphor screen, which has a little astigmatism, so it may not be as clear as a daytime telescope. Tiny black spots may be seen in the image, which is a natural phenomenon caused by the process of manufacturing the intensifier tube, not a quality problem.

3. What is the difference between night vision goggles and binoculars?
A telescope is an optical instrument that directly uses a lens to magnify the viewing angle of an object on the retina. It does not use a power source and cannot be viewed in a dark or low-light environment; a night vision device is an instrument that uses the principle of image enhancement or infrared imaging to observe. It is not as good as a telescope, but it is suitable for viewing in total darkness or under starlight and moonlight.

4. Why are active night vision devices suitable for civilian use?
Night vision goggles with active features have an IR light that emits a beam of infrared light to illuminate the scene. Therefore, the image is clear, but the infrared light emitted actively is easily detected by the enemy's instruments and exposes the target, so it is eliminated in the military, but there is no problem of exposure for civilian use, so the disadvantages become advantages, plus the price Inexpensive, so night vision goggles with active infrared are suitable for civilian use.