Photonics Dictionary

A camera designed to record astronomical objects (e.g., stars, planets, nebulae, galaxies) and their spectra.

An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It serves as the primary optical element responsible for gathering and...

A facility designed for the observation and recording of astronomical phenomena.

The use of photographs to record astronomical objects and phenomena for purposes of physical observation and measurement of motion, radiation and spectra.

Any irregular motion, variation in intensity or change in color that arises because of atmospheric turbulence during the observation of an astronomical phenomenon or object.

An instrument that photographs the spectra of an extraterrestrial object.

The process of using a spectrograph with a telescope to acquire information on an astronomical object's speed and physical characteristics.

An astronomical telescope is a type of optical instrument designed to gather and magnify light from distant celestial objects for observation and analysis. It typically consists of two main optical...

The unit generally used to express distances within the solar system, and sometimes to measure interstellar distances. Technically, one astronomical unit is the mean distance between the Earth and...

Any instrument or system carried by a balloon to the upper atmosphere to measure and record atmospheric information, such as radiation observations, while reducing atmospheric interference.

A simple form of astronomical telescope that uses a fixed objective and a focusable eyepiece. The objective forms an intermediate image in the instrument, resulting in an image that appears upside...

Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of atmospheric distortions. The Earth's atmosphere can cause light passing through it...

A two-mirror corrector for a parabolic primary mirror that provides anastigmatic performance for large astronomical telescopes.

A two-mirror lens design used in astronomical telescopes, the primary being a parabola, the secondary a smaller hyperbola. The image formed is free of spherical aberration and color and is located...

A charge-coupled device (CCD) is a type of electronic image sensor used in various imaging devices, including digital cameras, camcorders, and scientific instruments. It consists of an integrated...

An astronomical scanning technique for capturing images of stars without moving the sensor. To perform a drift scan, a CCD sensor's readout rate must be synchronized with the motion of celestial...

The effect of a powerful gravitational field on light traveling through the field. This effect is detectable in astronomical observations when light from a distant source passes a massive object...

A holographic grating is a type of diffraction grating that is produced using holographic recording techniques. It consists of a periodic structure of alternating transparent and opaque regions,...

Astronomical detector consisting of a photocathode isolated from the target by a coin value from which electrons are focused on a nuclear emission, producing tracks on the emission. Track density can...

A liquid crystal light valve (LCLV), also known as a spatial light modulator (SLM), is an optical device that modulates the intensity, phase, or polarization of light passing through it using liquid...

Luminosity refers to the total amount of energy emitted by an astronomical object, typically measured per unit time. It quantifies the intrinsic brightness of the object and is often expressed in...

A mid-infrared camera is a type of imaging device designed to capture images in the mid-infrared (mid-IR) spectral range, typically spanning wavelengths from approximately 3 to 12 µm. This...

An image-forming system having curved mirrors in place of transparent glass components. Mirror lenses are commonly used for astronomical purposes as well as cheap solutions for very long focal length...

1. A prism used in some instruments to bend light 90° before it enters the objective. 2. A dispersing prism located in front of an astronomical telescope objective to produce spectra of all...

A measure of the optical path length for light traveling from the sun or other celestial source through Earth's atmosphere to sea-level relative to the optical path length traveled by light from the...

A phase screen, in the context of optics and wave optics, refers to a surface or medium that introduces a phase delay to an incident wavefront passing through it. This concept is often used in the...

A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely used in various applications where high sensitivity, fast response times,...

An astronomical body that emits radiation concentrated by a strong magnetic field into two beams that rotate, giving a pulsing effect.

A contraction of quasi stellar. An astronomical object that appears to be a star but has a different, larger redshift.

An image-forming system that uses mirrors rather than lenses. Such objectives are frequently used for astronomical telescopes and in ultraviolet microscopes.

Frequently used in astronomical measurement, it is based on the diurnal rotation of a star relative to the fixed stellar system.

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...

The base used to hold an astronomical telescope. It may be either altazimuth, with horizontal and vertical axes of rotation, or equatorial, with one axis parallel to the Earth's axis of rotation and...

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...