Reflecting telescopes are the other type of optical telescope. Sir Isaac Newton made the first reflecting telescope in 1668. There are two main designs of reflecting telescopes, the Newtonian design and the Cassegrain design. In the Newtonian design, a concave mirror reflects the light from the sky to a flat, smaller mirror (or sometimes prism), that diverts the light to an eyepiece located on the side of the tube. In the Cassegrain design the light reflects back through a small hole that is cute in the centre of the main mirror. …
