A reflecting telescope that uses mirrors to collect and focus incoming light. A curved primary mirror at the back end of the scope collects light and reflects it back towards a flat secondary mirror at the top of the scope, which in turn reflects it out of the side at a convenient viewing angle. Newtonian scopes are usually mounted on equatorial mounts. Dobsonian telescopes have the same optical arrangement as a Newtonian but are mounted on simpler altazimuth mounts.
The first Newtonian telescope was developed by Sir Isaac Newton in 1668 and the design today remains a popular choice for amateur astronomers.