Night-Vision Goggles

Open to everyone until Thursday, October 1

To keep it, print it while it is open.

Night-vision goggles take in faint moonlight or starlight. They turn photons into electrons, multiply the electrons in tiny channels, and make a green image on a phosphor screen.

In the picture

Objective lens: gathers faint light from the dark scene.
Photocathode plate: converts incoming photons into electrons.
Microchannel plate: multiplies electrons through many tiny channels.
Phosphor screen: turns the electron stream into visible green light.
Eyepiece: lets the eye view the brightened green image.

Examples

A soldier watching a dark field through night-vision goggles.
A wildlife observer spotting nocturnal animals without a bright flashlight.

Key takeaways

Faint light is amplified electronically, not by making the scene brighter with lamps.
The image appears green because a phosphor screen glows when electrons hit it.