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Ellipsoidal reflector spot (abbreviated to ERS, or colloquially ellipsoidal or ellipse) is the name for a type of stage lighting instrument, named for the ellipsoidal reflector used to collect and direct the light through a barrel that contains a lens or lens train. The optics of an ERS instrument are roughly similar to those of a 35 mm slide ...
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic ...
The Byzantine architect Anthemius of Tralles (c. 600) described how this method could be used to construct an elliptical reflector, [13] and it was elaborated in a now-lost 9th-century treatise by Al-Ḥasan ibn Mūsā. [14] A similar method for drawing confocal ellipses with a closed string is due to the Irish bishop Charles Graves.
Rival lighting company, Kliegl Brothers, released their own Elipsoidial Reflector Spotlight that same year, calling it "Klieglight". It is unclear which company was first to develop the new technology, but both had developed the technology earlier and had to wait until a lamp was developed by GE that would work in the new fixture.
Main types of parabolic antennas. An offset dish antenna or off-axis dish antenna is a type of parabolic antenna.It is so called because the antenna feed is offset to the side of the reflector, in contrast to the common "front-feed" parabolic antenna where the feed antenna is suspended in front of the dish, on its axis.
Generally this would require the reflector to be placed at 1 ⁄ 4 of a wavelength behind the elements, and this can be seen in many common reflector arrays like television antennas. However, there are a number of factors that can change this distance, and actual reflector positioning varies.
A beam waveguide antenna is a type of complicated Cassegrain antenna with a long radio wave path to allow the feed electronics to be located at ground level. It is used in very large steerable radio telescopes and satellite ground antennas, where the feed electronics are too complicated and bulky, or requires too much maintenance and alterations, to locate on the dish; for example those using ...
Newtonian telescope design. A Newtonian telescope is composed of a primary mirror or objective, usually parabolic in shape, and a smaller flat secondary mirror.The primary mirror makes it possible to collect light from the pointed region of the sky, while the secondary mirror redirects the light out of the optical axis at a right angle so it can be viewed with an eyepiece.