... super achromatic optical system,better optical performance for 6 achromatic refractor telescope - doublet achromatic objective lenses,additionalfocus reducer for super ... adapter and camera adapter for your option.other super achromatic refractor telescope:5inch,D=127mm,f=635mm,other objective size ... D=102mm,f=1000mm,4inch,D=102mm,f=660mm.other ED APO refractor telescope:3.15inch,D=80mm,f=480mm,4inch,D ...