Editing Reflecting telescope (section)

===Newtonian===

[[File:Newtonian telescope2.svg|thumb|500px|Light path in a Newtonian telescope.]]

{{Main|Newtonian telescope}}

{{See also|Schmidt–Newton telescope}}

The '''[[Newtonian telescope]]''' was the first successful reflecting telescope, completed by [[Isaac Newton]] in 1668. It usually has a paraboloid primary mirror but at [[F-number|focal ratio]]s of about f/10 or longer a spherical primary mirror can be sufficient for high visual resolution. A flat secondary mirror reflects the light to a focal plane at the side of the top of the telescope tube. It is one of the simplest and least expensive designs for a given size of primary, and is popular with [[amateur telescope making|amateur telescope makers]] as a home-build project.
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