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Helios Dust Instrumentation
The Helios 1 and 2 spacecraft each carried two dust instruments to characterize the Zodiacal dust cloud inside the Earth’s orbit down to spacecraft positions 0.3 AU from the sun. The ''Zodiacal light instrument'' measured the brightness of light scattered by interplanetary dust along the line of sight. The in situ ''Micrometeoroid analyzer'' recorded impacts of meteoroids onto the sensitive detector surface and characterized their composition. The instruments delivered radial profiles of their measured data. Comet or meteoroid streams, and even interstellar dust were identified in the data. Overview The two Helios spacecraft were the result of a joint venture of West Germany's space agency DLR and NASA. The spacecraft were built in Germany and launched from Cape Canaveral Air Force Station, Florida. Helios 1 was launched in December 1974 onto an elliptic orbit between 1 and 0.31 AU. Helios 2 followed in January 1976 and reached 0.29 AU perihelion distance. The orbital period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helios Dust1
In ancient Greek religion and mythology, Helios (; grc, , , Sun; Homeric Greek: ) is the god and personification of the Sun (Solar deity). His name is also Latinized as Helius, and he is often given the epithets Hyperion ("the one above") and Phaethon ("the shining"). Helios is often depicted in art with a radiant crown and driving a horse-drawn chariot through the sky. He was a guardian of oaths and also the god of sight. Though Helios was a relatively minor deity in Classical Greece, his worship grew more prominent in late antiquity thanks to his identification with several major solar divinities of the Roman period, particularly Apollo and Sol. The Roman Emperor Julian made Helios the central divinity of his short-lived revival of traditional Roman religious practices in the 4th century AD. Helios figures prominently in several works of Greek mythology, poetry, and literature, in which he is often described as the son of the Titans Hyperion and Theia and brother of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zodiacal Light
The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direction in a roughly triangular shape along the zodiac, and appears with less intensity and visibility along the whole ecliptic as the zodiacal band. Zodiacal light spans the entire sky and contributes to the natural light of a clear and moonless night sky. A related phenomenon is ''gegenschein'' (or ''counterglow''), sunlight backscattered from the interplanetary dust, appearing directly opposite to the Sun as a faint but slightly brighter oval glow. Zodiacal light is very faint, often outshined and rendered invisible by moonlight or light pollution. The interplanetary dust in the Solar System forms a thick, pancake-shaped cloud called the zodiacal cloud which straddles the ecliptic plane. The particle sizes range from 10 to 300 micrometres, im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Ionization
Impact ionization is the process in a material by which one energetic charge carrier can lose energy by the creation of other charge carriers. For example, in semiconductors, an electron (or Electron hole, hole) with enough kinetic energy can knock a bound electron out of its bound state (in the valence band) and promote it to a state in the conduction band, creating an electron-hole pair. For carriers to have sufficient kinetic energy a sufficiently large electric field must be applied, in essence requiring a sufficiently large voltage but not necessarily a large current. If this occurs in a region of high electrical field then it can result in avalanche breakdown. This process is exploited in avalanche diodes, by which a small optical signal is amplifier, amplified before entering an external electronic circuit. In an avalanche photodiode the original charge carrier is created by the absorption of a photon. The impact ionization process is used in modern cosmic dust detectors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometeoroids
A micrometeoroid is a tiny meteoroid: a small particle of rock in space, usually weighing less than a gram. A micrometeorite is such a particle that survives passage through Earth's atmosphere and reaches Earth's surface. The term "micrometeoroid" was officially deprecated by the IAU in 2017, as redundant to meteoroid. Origins and orbits Micrometeoroids are very small pieces of rock or metal broken off from larger chunks of rock and debris often dating back to the birth of the Solar System. Micrometeoroids are extremely common in space. Tiny particles are a major contributor to space weathering processes. When they hit the surface of the Moon, or any airless body (Mercury, the asteroids, etc.), the resulting melting and vaporization causes darkening and other optical changes in the regolith. Micrometeoroids have less stable orbits than meteoroids, due to their greater surface area to mass ratio. Micrometeoroids that fall to Earth can provide information on millimeter scale h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helios E10a
In ancient Greek religion and mythology, Helios (; grc, , , Sun; Homeric Greek: ) is the god and personification of the Sun (Solar deity). His name is also Latinized as Helius, and he is often given the epithets Hyperion ("the one above") and Phaethon ("the shining"). Helios is often depicted in art with a radiant crown and driving a horse-drawn chariot through the sky. He was a guardian of oaths and also the god of sight. Though Helios was a relatively minor deity in Classical Greece, his worship grew more prominent in late antiquity thanks to his identification with several major solar divinities of the Roman period, particularly Apollo and Sol. The Roman Emperor Julian made Helios the central divinity of his short-lived revival of traditional Roman religious practices in the 4th century AD. Helios figures prominently in several works of Greek mythology, poetry, and literature, in which he is often described as the son of the Titans Hyperion and Theia and brother of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dornier Flugzeugwerke
Dornier Flugzeugwerke was a German aircraft manufacturer founded in Friedrichshafen in 1914 by Claude Dornier. Over the course of its long lifespan, the company produced many designs for both the civil and military markets. History Originally Dornier Metallbau, Dornier Flugzeugwerke took over Flugzeugbau Friedrichshafen production facilities ( Weingarten, Warnemünde, and the former Zeppelin shed at Manzell) when it failed in 1923. Dornier was well known between the two world wars as a manufacturer of large, all-metal flying boats and of land based airliners. The record-breaking 1924 Wal ( en, Whale) was used on many long distance flights and the Do X set records for its immense size and weight. Dornier's successful landplane airliners, including the Komet (''Comet'') and Merkur (''Mercury''), were used by Lufthansa and other European carriers during the 1920s and early 30s. Dornier built its aircraft outside Germany during much of this period due to the restrictions placed o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heidelberg
Heidelberg (; Palatine German language, Palatine German: ''Heidlberg'') is a city in the States of Germany, German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of students. Located about south of Frankfurt, Heidelberg is the List of cities in Baden-Württemberg by population, fifth-largest city in Baden-Württemberg. Heidelberg is part of the densely populated Rhine-Neckar, Rhine-Neckar Metropolitan Region. Heidelberg University, founded in 1386, is Germany's oldest and one of Europe's most reputable universities. Heidelberg is a Science, scientific hub in Germany and home to several internationally renowned #Research, research facilities adjacent to its university, including the European Molecular Biology Laboratory and four Max Planck Society, Max Planck Institutes. The city has also been a hub for the arts, especially literature, throughout the centurie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Max Planck Institute For Astronomy
The Max-Planck-Institut für Astronomie (Max Planck Institute for Astronomy, MPIA) is a research institute of the Max Planck Society (MPG). It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Königstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory. The institute primarily conducts basic research in the natural sciences in the field of astronomy. In addition to its own astronomical observations and astronomical research, the Institute is also actively involved in the development of observation instruments. The instruments or parts of them are manufactured in the institute's own workshops. History The founding of the institute in 1967 resulted from the insight that a supra-regional institute equipped with powerful telescopes was necessary in order to conduct internationally competitive astronomical research. Hans Elsässer, an astronomer, became the founding director in 1968. In February 1969, a first grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zodiacal Light
The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direction in a roughly triangular shape along the zodiac, and appears with less intensity and visibility along the whole ecliptic as the zodiacal band. Zodiacal light spans the entire sky and contributes to the natural light of a clear and moonless night sky. A related phenomenon is ''gegenschein'' (or ''counterglow''), sunlight backscattered from the interplanetary dust, appearing directly opposite to the Sun as a faint but slightly brighter oval glow. Zodiacal light is very faint, often outshined and rendered invisible by moonlight or light pollution. The interplanetary dust in the Solar System forms a thick, pancake-shaped cloud called the zodiacal cloud which straddles the ecliptic plane. The particle sizes range from 10 to 300 micrometres, im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronograph
A coronagraph is a telescopic attachment designed to block out the direct light from a star so that nearby objects – which otherwise would be hidden in the star's bright glare – can be resolved. Most coronagraphs are intended to view the corona of the Sun, but a new class of conceptually similar instruments (called ''stellar coronagraphs'' to distinguish them from ''solar coronagraphs'') are being used to find extrasolar planets and circumstellar disks around nearby stars as well as host galaxies in quasars and other similar objects with active galactic nuclei (AGN). Invention The coronagraph was introduced in 1931 by the French astronomer Bernard Lyot; since then, coronagraphs have been used at many solar observatories. Coronagraphs operating within Earth's atmosphere suffer from scattered light in the sky itself, due primarily to Rayleigh scattering of sunlight in the upper atmosphere. At view angles close to the Sun, the sky is much brighter than the background co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stray Light
Stray light is light in an optical system, which was not intended in the design. The light may be from the intended source, but follow paths other than intended, or it may be from a source other than the intended source. This light will often set a working limit on the dynamic range of the system; it limits the signal-to-noise ratio or contrast ratio, by limiting how dark the system can be. Ocular straylight is stray light in the human eye. Optical systems Monochromatic light Optical measuring instruments that work with monochromatic light, such as spectrophotometers, define stray light as light in the system at wavelengths (colors) other than the one intended. The stray light level is one of the most critical specifications of an instrument. For instance, intense, narrow absorption bands can easily appear to have a peak absorption less than the true absorption of the sample because the ability of the instrument to measure light transmission through the sample is limited by the st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photomultiplier
A photomultiplier is a device that converts incident photons into an electrical signal. Kinds of photomultiplier include: * Photomultiplier tube, a vacuum tube converting incident photons into an electric signal. Photomultiplier tubes (PMTs for short) are members of the class of vacuum tubes, and more specifically vacuum phototubes, which are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. ** Magnetic photomultiplier, developed by the Soviets in the 1930s. ** Electrostatic photomultiplier, a kind of photomultiplier tube demonstrated by Jan Rajchman of RCA Laboratories in Princeton, NJ in the late 1930s which became the standard for all future commercial photomultipliers. The first mass-produced photomultiplier, the Type 931, was of this design and is still commercially produced today. * Silicon photomultiplier, a solid-state device converting incident photons into an electric signal. Silicon photomultiplie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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