Newtonian Telescope

Newton’s studies on light and optics showed that a piece of glass would bend the light of some colors more than others, so that any telescope using a lens would distort the image. Although he may have heard about the idea of telescopes built from curved mirrors before, he was the first to design and build such a telescope. It used a shiny metal mirror, and a small secondary mirror that diverted the cone of light to the side where an observer could view it without getting in the way of the incoming beam of light. A replica of his telescope is shown at right.