Binocular
literally, having two eyes or pertaining to both eyes; an instrument having two tubes, each furnished above with an eyeglass, so as to enable one to see with both eyes at once.
Many opera glasses, telescopes, and microscopes are now binocular.
Binocular Eye Piece. - An eye piece so constructed and applied to the object glass as to divide the optical pencil transmitted to the latter, and form, as to each part of the divided pencil, a real or virtual image of the object beyond the place of division.
BINYON Binocular Microscope. - A microscope with two eyeglasses, so that both eyes may use it simultaneously.
Binocular Telescope. - A pair of telescopes mounted in a stand, and having a parallel adjustment for the width between the eyes. The tubes have a coincident horizontal and vertical adjustment for altitude and azimuth. The inventor of this instrument is said to have been a Capuchin monk, Schyrleus de Rheita.
Galileo also made a binocular telescope in 1617.