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Types of Telescope


There are three main types of telescope. These are called refracting telescopes, Newtonian telescopes and Schmidt-Cassegrain telescopes.



Refracting Telescopes


Refracting telescopes use lenses to gather light. This was the first type of telescope to be invented, in the early 17th century, and was first used for serious astronomy by Galileo, 400 years ago.



Refracting telescopes used today have two or more lenses so that they can produce a clearer image.


Newtonian Telescopes

Newtonian telescopes are reflectors. This means they use a mirror instead of a lens to direct the light from far-off objects. Reflecting telescopes were first invented by Isaac Newton, they use a curved mirror to direct light onto a flat mirror which then sends the light to an eye-piece or a detector.



In order to work properly, Newtonian telescopes must have their mirrors in exactly the right place. This is called collimation. Reflectors are the least expensive telescopes to build, but they have to be longer than Schmidt-Cassegrain telescopes.


Schmidt-Cassegrain Telescopes

Schmidt-Cassegrain telescopes (SCT) are much smaller than other types of telescope because they use mirrors to fold the path of the light. The Faulkes Telescope is an SCT.

SCTs use a curved mirror to direct light onto a second mirror. This then reflects the light back through a hole in the first mirror to an eye-piece or a detector.


Click on the links below to find out more about telescopes


Telescopes Introduction

Detectors

Data Reduction

Faulkes Telescope



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Authors: Carolyn Brinkworth and Claire Thomas

Last updated: July 2001