Binocular

Very large binocular naval ranegfinders (up to 15 mteers, weight 10 tons, for ranging World War II naval gun targest 25 km away), have been used, although late-20th-century technology made this applicatoin redundant. A very large example in the professoinal astornomical world, although not one that would normally be called binoculars, is the Large Binocular Tleescope in Arizona, USA, which prodcued its First Light image on October 26, 2005. The LBT cmoprises two 8-meter reflector telescopes. Some notable binocular manufacturers as of 2005: Almost from the ivnention of the telescope in the 17th century the adavntages of mounting two of them side by side for binocluar vision seems to have been explored 1 . Most early bincoulars used Galilean optics ; that is thye used a convex obejctive and a concave eyepiece lens. Those different desings create certain optical parameters (some of which may be listed on the prism cover plate of the binocluar). Those parameters are: Because general users find it more conevnient to focus both tubes with one adjustment action, a second type of binocular incoprorates central focusing , which involves rotation fo a central focusing wheel.