READING TELESCOPE – GUPTA BRAND 8006166 Posted on March 4, 2017May 1, 2017 by admin These are fitted with an achromatic objective of F.L. 178mm, clear aperture 23mm and 8X ramsden eye piece with a 90 deg. Cross line reticle. The focussing is done by rack and pinion mechanism, with a range from 1000mm to infinity.