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In astronomy, a photometric system is a set of well-defined passbands (or optical filters), with a known sensitivity to incident radiation. The sensitivity usually depends on the optical system, detectors and filters used. For each photometric system a set of primary standard stars is provided. A commonly adopted standardized photometric system is the Johnson-Morgan or UBV photometric system (1953). At present, there are more than 200 photometric systems. Photometric systems are usually characterized according to the widths of their passbands: * broadband (passbands wider than 30 nm, of which the most widely used is Johnson-Morgan UBV system) * intermediate band (passbands between 10 and 30 nm wide) * narrow band (passbands less than 10 nm wide) Photometric letters Each letter designates a section of light of the electromagnetic spectrum; these cover well the consecutive major groups, near-ultraviolet (NUV), visible light (centered on the V band), near-infrared ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around 1 millimeter (300 GHz) to the nominal red edge of the visible spectrum, around 700 nanometers (430 THz). Longer IR wavelengths (30 μm-100 μm) are sometimes included as part of the terahertz radiation range. Almost all black-body radiation from objects near room temperature is at infrared wavelengths. As a form of electromagnetic radiation, IR propagates energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires emit invisible heat; in 1681 the pioneering experimenter Edme Mariotte showed that glass, though transparent to sunlight, obstructed radiant heat. In 1800 the astronomer Sir William Herschel discovered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest include planets, natural satellite, moons, stars, nebulae, galaxy, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond atmosphere of Earth, Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonian astronomy, Babylonians, Greek astronomy, Greeks, Indian astronomy, Indians, Egyptian astronomy, Egyptians, Chinese astronomy, Chinese, Maya civilization, Maya, and many anc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanometre
330px, Different lengths as in respect to the molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American and British English spelling differences#-re, -er, American spelling) is a units of measurement, unit of length in the International System of Units (SI), equal to one billionth (short scale) of a metre () and to 1000 picometres. One nanometre can be expressed in scientific notation as , and as metres. History The nanometre was formerly known as the millimicrometre – or, more commonly, the millimicron for short – since it is of a micron (micrometre), and was often denoted by the symbol mμ or (more rarely and confusingly, since it logically should refer to a ''millionth'' of a micron) as μμ. Etymology The name combines the SI prefix ''nano-'' (from the Ancient Greek , ', "dwarf") with the parent unit name ''metre'' (from Greek , ', "unit of measurement"). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaia (spacecraft)
''Gaia'' is a space observatory of the European Space Agency (ESA), launched in 2013 and expected to operate until 2025. The spacecraft is designed for astrometry: measuring the positions, distances and motions of stars with unprecedented precision. The mission aims to construct by far the largest and most precise 3D space catalog ever made, totalling approximately 1 billion astronomical objects, mainly stars, but also planets, comets, asteroids and quasars, among others. To study the precise position and motion of its target objects, the spacecraft monitored each of them about 70 times over the five years of the nominal mission (2014–2019), and continues to do so during its extension. The spacecraft has enough micro-propulsion fuel to operate until about November 2024. As its detectors are not degrading as fast as initially expected, the mission could therefore be extended. ''Gaia'' targets objects brighter than magnitude 20 in a broad photometric band that covers the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AKARI
Akari (ASTRO-F) was an infrared astronomy Infrared astronomy is a sub-discipline of astronomy which specializes in the observation and analysis of astronomical objects using infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers, and falls in betwee ... space observatory, satellite developed by Japan Aerospace Exploration Agency, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006, at 21:28 Coordinated Universal Time, UTC (06:28, 22 February Japan Standard Time, JST) by M-V rocket into Earth sun-synchronous orbit. After its launch it was named ''Akari'' (明かり), which means ''light'' in Japanese. Earlier on, the project was known as IRIS (InfraRed Imaging Surveyor). Its primary mission was to survey the entire sky in near-, mid- and far-infrared, through its aperture telescope. Technical design Its designed lifespan, of far- and mid-infrared sensors, was 550 days, limited by its liquid helium co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Near Infrared Survey
The Deep Near Infrared Survey of the Southern Sky (DENIS) was a deep astronomical survey of the southern sky in the near-infrared and optical wavelengths, using an ESO 1-meter telescope at the La Silla Observatory. It operated from 1996 to 2001. See also * DENIS-P J1058.7-1548 * DENIS-P J1228.2-1547 * DENIS-P J020529.0-115925 * DENIS-P J082303.1-491201 b * DENIS-P J101807.5-285931 * DENIS J024011.0-014628,6dFGS gJ024011.1-014628 * Edinburgh-Cape Blue Object Survey The Edinburgh-Cape Blue Object Survey (or EC in astronomical notation)C. Aerts, J. Christensen-Dalsgaard, D. W. Kurtz, ''Asteroseismology'' (2010), p. 105. is a major astronomical survey to discover blue stellar objects brighter than B~18 in the so ... References External links DENIS—Deep Near Infrared Survey of the Southern SkyESO 1-metre telescope Astronomical catalogues Astronomical surveys {{astronomical-catalogue-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Energy Survey
The Dark Energy Survey (DES) is an astronomical survey designed to constrain the properties of dark energy. It uses images taken in the near-ultraviolet, Visible spectrum, visible, and near-infrared to measure the expansion of the universe using Type Ia supernovae, baryon acoustic oscillations, the number of Galaxy groups and clusters, galaxy clusters, and weak gravitational lensing. The collaboration is composed of research institutions and universities from the United States,DES Collaboration Page DES Collaborators. Australia, Brazil,DES-Brazil , DES-Brazil Consortium. the United Kingdom, Germany, Spain, and Switzerland. The collaboration is divided into several scientific working groups. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NOAO
The National Optical Astronomy Observatory (NOAO) was the United States national observatory for ground-based nighttime ultraviolet-optical-infrared (OUVIR) astronomy. The National Science Foundation (NSF) funded NOAO to provide forefront astronomical research facilities for US astronomers. Professional astronomers from any country in the world could apply to use the telescopes operated by NOAO under the NSF's "open skies" policy. NOAO was operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the NSF. Its headquarters in Tucson, Arizona were co-located with the headquarters of the National Solar Observatory. The budget for NOAO during the 2017 fiscal year was nearly $23 million. NOAO was founded in 1984 to join the operations of the Kitt Peak National Observatory in the United States with the Cerro Tololo Inter-American Observatory in Chile. On October 1, 2019, NOAO merged its operations with the Gemini Observatory and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerro Tololo Inter-American Observatory
The Cerro Tololo Inter-American Observatory (CTIO) is an astronomical observatory located on Cerro Tololo in the Coquimbo Region of northern Chile, with additional facilities located on Cerro Pachón about to the southeast. It is approximately east of La Serena, where support facilities are located. The site was identified by a team of scientists from Chile and the United States in 1959, and it was selected in 1962. Construction began in 1963 and regular astronomical observations commenced in 1965. Construction of large buildings on Cerro Tololo ended with the completion of the Víctor Blanco Telescope in 1974, but smaller facilities have been built since then. Cerro Pachón is still under development, with two large telescopes (Gemini South and SOAR) inaugurated since 2000, and one in the early stages of construction (the Vera C. Rubin Observatory) The principal telescopes at CTIO are the 4 m Víctor M. Blanco Telescope, named after Puerto Rican astronomer Víctor Manuel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chandra X-ray Observatory
The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, enabled by the high angular resolution of its mirrors. Since the Earth's atmosphere absorbs the vast majority of X-rays, they are not detectable from Earth-based telescopes; therefore space-based telescopes are required to make these observations. Chandra is an Earth satellite in a 64-hour orbit, and its mission is ongoing . Chandra is one of the Great Observatories, along with the Hubble Space Telescope, Compton Gamma Ray Observatory (1991–2000), and the Spitzer Space Telescope (2003–2020). The telescope is named after the Nobel Prize-winning Indian-American astrophysicist Subrahmanyan Chandrasekhar. Its mission is similar to that of ESA's XMM-Newton spacecraft, also launched in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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