A binoviewer is an

optical Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultravio ...

device designed to enable binocular viewing through a single objective. Binoviewer

In contrast to

binoculars Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most binoculars are sized to be held ...

, it allows partially stereoscopic viewing and partially monocular viewing, this because the eyes and brain still process the image binocularly, as both images are produced by the same objective and do not differ except for aberrations induced by the binoviewer itself. A binoviewer consists of a

beam splitter A beam splitter or beamsplitter is an optical instrument, optical device that splits a beam of light into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as Interferometry, int ...

which splits the image provided by the objective into two identical (but fainter) copies, and a system of prisms or mirrors that relay the images to a pair of identical

eyepiece An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as Optical telescope, telescopes and microscopes. It is named because it is usually the lens that is closest to the eye when someone looks thro ...

s. Binoviewers are a standard component of laboratory

microscopes A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...

and are also used with

optical telescope An optical telescope gathers and focus (optics), focuses light mainly from the visible spectrum, visible part of the electromagnetic spectrum, to create a magnification, magnified image for direct visual inspection, to make a photograph, or to co ...

s, particularly in

amateur astronomy Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the Naked eye, unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, some amateur astr ...

. Trinocular splitters are also used, where a camera is to be attached as well.

References

Optical devices Microscope components {{optics-stub