Photonics Dictionary

A handheld navigational instrument used to measure the elevation angle of celestial bodies such as the sun. An image of the sun is viewed through a small telescope via two plane mirrors so that any...

A passive infrared system that uses two line-of-sight telescopes to generate both narrow and wide field-of-view images of the same target area, which can be presented on a single split screen or on...

A high-power riflescope specifically intended for sighting and shooting distant targets.

A spatial light modulator (SLM) is an optical device that modulates or manipulates the amplitude, phase, or polarization of light in two dimensions, typically in the form of an array. SLMs are...

A technique for obtaining improved resolution of images produced by large telescopes and distorted by the effects of atmospheric turbulence. Many individual exposures are recorded at high speeds by a...

Two stars so close together that they cannot be resolved by telescopes. They are proved to be double stars by the doubling of their spectral lines.

A spheric lens, also known as a spherical lens, is a type of optical lens with at least one surface that is part of a sphere. This means that the lens surface is curved in a symmetrical manner,...

A telescopic light-sensing meter used to measure illumination levels of small regions at a distance of many feet; it is used in professional motion picture and television production to ensure proper...

Instruments used for measuring angles and occasionally lengths on the ground. The principal surveying instruments are the level, the stadia telescope, the transit and the theodolite. Laser...

A small telescope mounted on a tripod and free to rotate about a vertical axis. A spirit level is mounted over the telescope and adjusted so that when the bubble is central, the telescope axis is...

An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small telescope, and a mirror in the focal plane reflects an internal illuminated surface...

Teloscopy, while not a commonly used term, could be understood in the context of principles related to telescopes and their applications in observation and measurement. If we interpret teloscopy as...

A precise telescope set on a pair of rotation axes, the horizontal and vertical axes equipped with two divided circles. One circle measures horizontal angles and the other measures vertical angles....

A controlled motion system that may use a telescope, camera or antenna to follow accurately a satellite, missile, vehicle or other device in response to radar, radio or computer signals.

A color-television viewing system with three kinescopes, three lenses and three deflection yokes used to form the red, green and blue images required for a tricolor television projection.

Ultraviolet (UV) coatings are specialized optical coatings designed to operate in the ultraviolet region of the electromagnetic spectrum, typically ranging from 10 nm to 400 nm. These coatings are...

In optics, the term vacuum typically refers to a space devoid of matter, including air and other gases. However, in practical terms, achieving a perfect vacuum, where there is absolutely no matter...

Consists of a pair of radio telescopes concentrated on a single celestial object. This technique creates a single radio telescope with a diameter equal to the distance between the pair, which allows...

A pair of stars (double star) that can be seen separately with a telescope, generally by setting a filar micrometer for the separation and position angle. Observation of visual binaries improves with...

Conventional coordinates for optical system analysis, the X-axis being the horizontal, the Y-axis the vertical and the Z-axis the optical axis of the system.

Zerodur is a type of glass ceramic material known for its exceptional thermal and mechanical properties, particularly its low coefficient of thermal expansion (CTE) close to zero. It was developed by...