Newton's telescope. Sir Isaac Newton's own drawing of his first reflecting telescope design. Newton invented the reflecting telescope in 1668. It worked by focusing light using a parabolic mirror (V). This reflected light back up the tube of the telescope to another mirror (D) which reflected it into the eyepiece (F). The design avoided the chromatic aberration and loss of light caused by the use of lenses and was highly successful; the largest modern telescopes are all of the reflect- ing variety. This first telescope was only 15 cm long and 2.5 cm in diameter but could magnify 30- 40 times. He built a second, larger version in 1671. Image taken from a 1672 letter by Newton.