Binoculars

Binoculars are a kind of tool that lets people see far-away things more clearly. The technology is called optics. Binoculars are made of a pair of matched telescopes which are held in front of the user's eyes.

The two telescopes of the pair have lenses that focus light and magnify the image. When someone looks through the binoculars at a far-away object, they can see details.

Early binoculars had two Galilean telescopes without prisms. Today most have prisms inside, which fold the light path to shorten the length of the tubes. That is why a binocular is shorter than standard telescopes of similar power.

Binoculars were invented in the 17th century. They allow a telescope user to use both eyes. The Royal Navy used single telescopes, but now all ships have heavy binoculars. Heavy ones can be mounted on swivels to scan the horizon. Binoculars are also standard issue in all armies. Night vision binoculars use photocathode electronics to intensify the image.

Binoculars are also used for theatre (opera glasses), birdwatching amateur astronomy, and generally watching the scenery.