Newtonian telescope Newtonian telescope The Newtonian telescope, also called the Newtonian reflector or just the Newtonian, is a type of reflecting telescope invented by the English scientist Sir Isaac Newton (1642–1727), using a concave primary mirror and a flat diagonal secondary mirror. Newton's first reflecting telescope was completed in 1668 and is the earliest known functional reflecting telescope. The Newtonian telescope's simple design makes it very popular with amateur telescope makers. Newton's idea for a reflecting telescope was not new. Galileo Galilei and Giovanni Francesco Sagredo had discussed using a mirror as the image forming objective soon after the invention of the
Galilean transformation and a "uniform motion" of spacetime. Let represent a point in three-dimensional space, and a point in one-dimensional time. A general point in spacetime is given by an ordered pair . A uniform motion, with velocity , is given by where . A translation is given by where and . A rotation is given by where is an orthogonal transformation. As a Lie group, the Galilean transformations span 10 dimensions, i.e., comprise 10 generators. Two Galilean transformations compose to form a third Galilean transformation, . The set of all Galilean transformations on space forms a group with composition as the