Editing Toroidal reflector

{{Short description|Type of reflecting telescope}}
A '''toroidal mirror''' is a reflector whose surface is a section of a [[torus]], defined by two radii of curvature.<ref>{{Cite journal |last=Rappaport |first=Carey |date=13 April 2015 |title=Multistatic nearfield imaging radar for portal security systems using a high gain toroidal reflector antenna |url=https://ieeexplore.ieee.org/document/7228246 |journal=2015 9th European Conference on Antennas and Propagation (EuCAP) |via=IEEE}}</ref> Such reflectors are easier to manufacture than mirrors with a surface described by a paraboloid or ellipsoid. They suffer from [[spherical aberration]] and [[coma_(optics)| coma]], but do not suffer from [[astigmatism]] like a [[spherical mirror]] when used in an off-axis geometry, provided the angle of incidence is matched to the design angle. Because they are easier to manufacture, they are much cheaper than ellipsoidal or paraboloidal mirrors for the same surface quality.

Toroidal mirrors are used in [[Reflecting_telescope#Yolo | Yolo telescopes]] and optical [[monochromator|monochromators]]. In these devices, the source and detectors of the light are not located on the optical axis of the mirror, so the use of a true paraboloid of revolution would cause a distorted image.

==See also==
* [[List of telescope types]]

== References ==
{{reflist}}

==External links==

* [https://web.archive.org/web/20040810021752/http://bhs.broo.k12.wv.us/homepage/alumni/dstevick/erwin_c.htm Toroidal mirrors for Yolo telescopes]

[[Category:Mirrors]]
[[Category:Telescope types]]


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