Isaak Newton (1642 - 1727). ... During 1665 - 1667 Newton made his three main discoveries: the method of fluxings and quadratures (differential and integral calculus, explanation of the light nature and the law of gravitation). ... In 1668 Newton built the first reflecting telescope. The big lens telescope gave indistinct image with painted edges. ... The scientist considered this problem indisolved and suggested a mean against chromatic aberration: a mirror must be used instead of objective lens. ...