OPTICS & OPTICAL PHENOMENA TELESCOPE EQUIPMENT A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site binoculars A pair of low-power prismatic spotting scopes mounted together for three-dimensional viewing. Prisms and/or porro mirrors shorten the instrument size and deliver a corrected image to the viewer. The common, incorrect usage, “a pair of binoculars,” really means two sets of twin oculars, or four oculars. Binoculars are specified by numbers such 10 × 50, the first of which gives the magnification and the second the aperture in millimeters. Good binoculars with a large aperture (50 mm or more) are a useful astronomical tool for comet-hunting and observing large star clusters and nebulae. Related categories    • OPTICS AND OPTICAL PHENOMENA    • TELESCOPE EQUIPMENT AND TECHNIQUES Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP