Optical instrument for viewing an object in magnification with both eyes; for example, field glasses and opera glasses. Binoculars consist of two telescopes containing lenses and prisms, which produce a stereoscopic effect as well as magnifying the image.
Use of prisms has the effect of “folding” the light path, allowing for a compact design.
The first binocular telescope was constructed by the Dutch inventor Hans Lippershey (c. 1570–c. 1619), in 1608. Later development was largely due to the German Ernst Abbé (1840–1905) of Jena, who at the end of the 19th century designed prism binoculars that foreshadowed the instruments of today, in which not only magnification but also stereoscopic effect is obtained.
eyeshot / aɪʃɑːt /
The range of the eye; view
field glass / ˈfiːld ˈɡlæs /
A small refracting telescope; SYN. glass, spyglass, field-glass
spyglass / spaɪɡlæs /
(Irregular plural: spyglasses).
A small telescope for viewing distant objects. spy-glass.