GENERAL KNOWLEDGE

Detailed explanation-1: -The Newtonian telescope, also called the Newtonian reflector or just a Newtonian, is a type of reflecting telescope invented by the English scientist Sir Isaac Newton, using a concave primary mirror and a flat diagonal secondary mirror.

Detailed explanation-2: -Isaac Newton built his reflecting telescope as a proof for his theory that white light is composed of a spectrum of colours. He had concluded that the lens of any refracting telescope would suffer from the dispersion of light into colours (chromatic aberration).