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Telecompressor or focal reducer: Optical element to decrease the telescope's focal length and magnification (usually by a fixed percentage) and widen the field of view, providing opposite effects of a Barlow lens. Star Diagonal: Used to change the angle of the light coming out of a telescope, for easier viewing.
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 Houghton telescope or Lurie–Houghton telescope is a design that uses a wide compound positive-negative lens over the entire front aperture to correct spherical aberration of the main mirror. If desired, the two corrector elements can be made with the same type of glass, since the Houghton corrector's chromatic aberration is minimal.
People demonstrating a Schmidt–Cassegrain telescope at a sidewalk gathering. The Schmidt–Cassegrain design is very popular with consumer telescope manufacturers because it combines easy-to-manufacture spherical optical surfaces to create an instrument with the long focal length of a refracting telescope with the lower cost per aperture of a reflecting telescope.
Extremely Large Telescope, Chile – 39.3 m (1,550 in). Construction began in 2018, first light planned in 2028. [23] Thirty Meter Telescope, Hawaii, USA – 30 m (1,200 in). Construction began in 2014 but halted in 2015; as of 2022 it has not resumed. [24] Giant Magellan Telescope, Chile – seven 8.4 m mirrors on a single mount. This provides ...
A typical sight mounting system consists of two parts, the scope rings and the scope base. The mounting generally positions the telescopic sight axis without cant over the receiver and bore center axis, to make sighting in and the use of ballistic tracking at various ranges for the user as easy as possible.
The Large Binocular Telescope at the Mount Graham International Observatory in Arizona uses two curved mirrors to gather light. An optical telescope gathers and focuses light mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct visual inspection, to make a photograph, or to collect data through electronic image sensors.
The 100-inch (2.54 m) Hooker reflecting telescope at Mount Wilson Observatory near Los Angeles, USA, used by Edwin Hubble to measure galaxy redshifts and discover the general expansion of the universe. A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. [1]