▁large ▁object ives ▁are ▁also ▁used ▁in ▁fixed ▁mount ings . ▁ ▁Very ▁large ▁bin oc ular ▁naval ▁range find ers ▁( up ▁to ▁ 1 5 ▁meters ▁separation ▁of ▁the ▁two ▁objective ▁l enses , ▁weight ▁ 1 0 ▁tons , ▁for ▁r anging ▁World ▁War ▁II ▁naval ▁gun ▁targets ▁ 2 5   km ▁away ) ▁have ▁been ▁used , ▁although ▁late - 2 0 th ▁century ▁technology ▁made ▁this ▁application ▁mostly ▁redundant . ▁ ▁Astronom ical ▁▁ ▁Bin oc ular s ▁are ▁widely ▁used ▁by ▁amateur ▁astronom ers ; ▁their ▁wide ▁field ▁of ▁view ▁makes ▁them ▁useful ▁for ▁com et ▁and ▁super n ova ▁seeking ▁( gi ant ▁bin oc ular s ) ▁and ▁general ▁observation ▁( port able ▁bin oc ular s ). ▁Bin oc ular s ▁specifically ▁ge ared ▁towards ▁astronom ical ▁view ing ▁will ▁have ▁larger ▁a pert ure ▁object ives ▁( in ▁the ▁ 7 0   mm ▁or ▁ 8 0   mm ▁range ) ▁because ▁the ▁diameter ▁of ▁the ▁objective ▁l ens ▁increases ▁the ▁total ▁amount ▁of ▁light ▁captured , ▁and ▁therefore ▁determ ines ▁the ▁f ain test ▁star ▁that ▁can ▁be ▁observed . ▁Bin oc ular s ▁designed ▁specifically ▁for ▁astronom ical ▁view ing ▁( o ften ▁ 8 0   mm ▁and ▁larger ) ▁are ▁sometimes ▁designed ▁without ▁pr isms ▁in ▁order ▁to ▁allow ▁maximum ▁light ▁transmission . ▁Such ▁bin oc ular s ▁also ▁usually ▁have ▁change able ▁e y ep ie ces ▁to ▁vary ▁magn ification . ▁Bin oc ular s