▁opt ics ; ▁that ▁is , ▁they ▁used ▁a ▁convex ▁objective ▁and ▁a ▁con ca ve ▁e y ep ie ce ▁l ens . ▁The ▁Gal ile an ▁design ▁has ▁the ▁advantage ▁of ▁present ing ▁an ▁ere ct ▁image ▁but ▁has ▁a ▁narrow ▁field ▁of ▁view ▁and ▁is ▁not ▁capable ▁of ▁very ▁high ▁magn ification . ▁This ▁type ▁of ▁construction ▁is ▁still ▁used ▁in ▁very ▁cheap ▁models ▁and ▁in ▁opera ▁glass es ▁or ▁the ater ▁glass es . ▁The ▁Gal ile an ▁design ▁is ▁also ▁used ▁in ▁low ▁magn ification ▁bin oc ular ▁surg ical ▁and ▁j ew el ers ' ▁l oup es ▁because ▁they ▁can ▁be ▁very ▁short ▁and ▁produce ▁ ▁an ▁u pr ight ▁image ▁without ▁extra ▁or ▁unusual ▁ere ct ing ▁opt ics , ▁reducing ▁exp ense ▁and ▁overall ▁weight . ▁They ▁also ▁have ▁large ▁exit ▁pup ils ▁making ▁cent ering ▁less ▁critical ▁and ▁the ▁narrow ▁field ▁of ▁view ▁works ▁well ▁in ▁those ▁applications . ▁These ▁are ▁typically ▁mounted ▁on ▁an ▁e y eg lass ▁frame ▁or ▁custom - fit ▁onto ▁e y eg lass es . ▁ ▁Bin oc ular s ▁with ▁Ke pler ian ▁opt ics ▁▁ ▁An ▁improved ▁image ▁and ▁higher ▁magn ification ▁is ▁achieved ▁in ▁bin oc ular s ▁employ ing ▁Ke pler ian ▁opt ics , ▁where ▁the ▁image ▁formed ▁by ▁the ▁objective ▁l ens ▁is ▁viewed ▁through ▁a ▁positive ▁e y ep ie ce ▁l ens ▁( oc ular ). ▁ ▁Since ▁the ▁Ke pler ian ▁configuration ▁produces ▁an ▁invert ed ▁image ,