Searchlight in the context of "Xenon arc lamp"

Sir Charles Algernon Parsons (13 June 1854 – 11 February 1931) was an Anglo-Irish mechanical engineer and inventor who designed the modern steam turbine in 1884. His invention revolutionised marine propulsion, and he was also the founder of C. A. Parsons and Company. He worked as an engineer on dynamo and turbine design, and power generation, with great influence in the naval and electrical engineering fields. He also helped develop optical equipment for searchlights and telescopes. Parsons received the Franklin Medal in 1920, the Faraday Medal in 1923, and the Copley Medal in 1928 for his work, as well as the Engineering Heritage Awards posthumously in 1995.

His inventions and developments were used in many appliances during the early 20th century, including both naval and optical devices. He was elected to the Royal Society in 1898, and he served as the president of the British Association between 1916 and 1919. For his lasting contributions, Parsons was knighted in 1911, and he became a member of the Order of Merit in 1927. He additionally received the Bessemer Gold Medal in 1929.

A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity. It functions similarly to a searchlight or flashlight reflector to direct radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic antennas have some of the highest gains, meaning that they can produce the narrowest beamwidths, of any antenna type. In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the wavelength of the radio waves used, so parabolic antennas are used in the high frequency part of the radio spectrum, at UHF and microwave (SHF) frequencies, at which the wavelengths are small enough that conveniently sized reflectors can be used.

Parabolic antennas are used as high-gain antennas for point-to-point communications, in applications such as microwave relay links that carry telephone and television signals between nearby cities, wireless WAN/LAN links for data communications, satellite communications, and spacecraft communication antennas. They are also used in radio telescopes.

A watchtower or guardtower (also spelt watch tower, guard tower) is a type of military/paramilitary or policiary tower used for guarding an area. Sometimes fortified, and armed with heavy weaponry, especially historically, the structures are built in areas of established control. These include military bases, cities occupied by military forces, prisons and more. A common equipment is searchlights.

It differs from a regular tower in that its primary use is military/policiary and from a turret in that it is usually a freestanding structure. Its main purpose is to provide a high, safe place from which a sentinel or guard may observe the surrounding area. In some cases, non-military towers, such as religious towers, may also be used as watchtowers.

The Tribute in Light is an art installation created in remembrance of the September 11 attacks. It consists of 88 vertical searchlights arranged in two columns of light to represent the Twin Towers. It stands six blocks south of the World Trade Center on top of the Battery Parking Garage in New York City. Tribute in Light began as a temporary commemoration of the attacks in early 2002, but it became an annual event, currently produced on September 11 by the Municipal Art Society of New York. The Tribute in Light was conceived by artists John Bennett, Gustavo Bonevardi, Richard Nash Gould, Julian LaVerdiere, and Paul Myoda, and lighting consultant Paul Marantz.

The Tribute's illumination begins at dusk and ends at dawn, with the lights being turned off for 20-minute periods to allow migratory birds to escape as needed. On clear nights, the lights can be seen from 60 miles (97 km) away, visible in all of New York City and most of suburban Northern New Jersey and Long Island. The lights can also be seen in Fairfield County, Connecticut, as well as Westchester, Orange, and Rockland counties in New York.

A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis. The parabolic reflector transforms an incoming plane wave travelling along the axis into a spherical wave converging toward the focus. Conversely, a spherical wave generated by a point source placed in the focus is reflected into a plane wave propagating as a collimated beam along the axis.

Parabolic reflectors are used to collect energy from a distant source (for example sound waves or incoming star light). Since the principles of reflection are reversible, parabolic reflectors can also be used to collimate radiation from an isotropic source into a parallel beam. In optics, parabolic mirrors are used to gather light in reflecting telescopes and solar furnaces, and project a beam of light in flashlights, searchlights, stage spotlights, and car headlights. In radio, parabolic antennas are used to radiate a narrow beam of radio waves for point-to-point communications in satellite dishes and microwave relay stations, and to locate aircraft, ships, and vehicles in radar sets. In acoustics, parabolic microphones are used to record faraway sounds such as bird calls, in sports reporting, and to eavesdrop on private conversations in espionage and law enforcement.

A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses (dioptrics) and curved mirrors (catoptrics). Catadioptric combinations are used in focusing systems such as searchlights, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses. Other optical systems that use lenses and mirrors are also referred to as "catadioptric", such as surveillance catadioptric sensors.

Avionics (a portmanteau of aviation and electronics) are the electronic systems used on aircraft. Avionic systems include communications, navigation, the display and management of multiple systems, and the hundreds of systems that are fitted to aircraft to perform individual functions. These can be as simple as a searchlight for a police helicopter or as complicated as the tactical system for an airborne early warning platform.

An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc).

The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the first decade of the 1800s, was the first practical electric light. It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent light in the early 20th century. It continued in use in more specialized applications where a high intensity point light source was needed, such as searchlights and movie projectors until after World War II. The carbon arc lamp is now obsolete for most of these purposes, but it is still used as a source of high intensity ultraviolet light.