Newtonians
The Newtonian telescope is a type of reflecting telescope invented by the British 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.

All Explore Scientific, Bresser and FirstLight Newtonians use parabolic primary mirrors, which focus all incoming rays of light into a single point on the secondary mirror.