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Uvicon
The Orbiting Astronomical Observatory 2 (OAO-2, nicknamed ''Stargazer'') was the first successful space telescope (first space telescope being OAO-1, which failed to operate once in orbit), launched on December 7, 1968. An Atlas-Centaur rocket launched it into a nearly circular altitude Earth orbit. Data was collected in ultraviolet on many sources including comets, planets, and galaxies. It had two major instrument sets facing in opposite directions; the Smithsonian Astrophysical Observatory (SAO) and the Wisconsin Experiment Package (WEP). One discovery was large halos of hydrogen gas around comets, and it also observed Nova Serpentis, which was a nova discovered in 1970. Celescope: Smithsonian Astrophysical Observatory The Smithsonian Astrophysical Observatory, also called Celescope, had four 12 inch (30.5 cm) Schwarzschild telescopes that fed into Uvicons. The Uvicon was an ultra-violet light detector based on the Westinghouse Vidicon. Ultraviolet light was converte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vidicon
Video camera tubes are devices based on the cathode-ray tube that were used in television cameras to capture television images, prior to the introduction of charge-coupled device (CCD) image sensors in the 1980s. Several different types of tubes were in use from the early 1930s, and as late as the 1990s. In these tubes, an electron beam is scanned across an image of the scene to be broadcast focused on a target. This generated a current that is dependent on the brightness of the image on the target at the scan point. The size of the striking ray is tiny compared to the size of the target, allowing 480–486 horizontal scan lines per image in the NTSC format, 576 lines in PAL, and as many as 1035 lines in Hi-Vision. Cathode-ray tube Any vacuum tube which operates using a focused beam of electrons, originally called cathode rays, is known as a cathode-ray tube (CRT). These are usually seen as display devices as used in older (i.e., non- flat panel) television receivers and comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up quark, up and down quark, down quarks. Electrons are extremely lightweight particles that orbit the positively charged atomic nucleus, nucleus of atoms. Their negative charge is balanced by the positive charge of protons in the nucleus, giving atoms their overall electric charge#Charge neutrality, neutral charge. Ordinary matter is composed of atoms, each consisting of a positively charged nucleus surrounded by a number of orbiting electrons equal to the number of protons. The configuration and energy levels of these orbiting electrons determine the chemical properties of an atom. Electrons are bound to the nucleus to different degrees. The outermost or valence electron, valence electrons are the least tightly bound and are responsible for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbiting Solar Observatory
The Orbiting Solar Observatory (abbreviated OSO) Program was the name of a series of American space telescopes primarily intended to study the Sun, though they also included important non-solar experiments. Eight were launched successfully into low Earth orbit by NASA between 1962 and 1975 using Delta rockets. Their primary mission was to observe an 11-year sun spot cycle in UV and X-ray spectra. The initial seven (OSO 1–7) were built by Ball Aerospace, then known as Ball Brothers Research Corporation (BBRC), in Boulder, Colorado.Todd Neff (2010From Jars to the Stars: How Ball Came to Build a Comet-Hunting Machine Denver, CO.: Earthview Media. OSO 8 was built by Hughes Space and Communications Company, in Culver City, California. History Nancy Roman oversaw the development of the Orbiting Solar Observatory program from 1961 to 1963. The basic design of the entire series featured a rotating section, the "Wheel", to provide gyroscopic stability. A second section, the "S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbiting Astronomical Observatory
The Orbiting Astronomical Observatory (OAO) satellites were a series of four American space observatories launched by NASA between 1966 and 1972, managed by NASA Chief of Astronomy Nancy Grace Roman. These observatories, including the first successful space telescope, provided the first high-quality observations of many objects in ultraviolet light. Although two OAO missions were failures, the success of the other two increased awareness within the astronomical community of the benefits of space-based observations, and led to the instigation of the Hubble Space Telescope. OAO-1 The first Orbiting Astronomical Observatory was launched successfully on 8 April 1966, carrying instruments to detect ultraviolet, X-ray and gamma ray emission. Before the instruments could be activated, a power failure resulted in the termination of the mission after three days. The spacecraft was out of control, so that the solar panels could not be deployed to recharge the batteries that would s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinction (astronomy)
In astronomy, extinction is the absorption (electromagnetic radiation), absorption and light scattering, scattering of electromagnetic radiation by dust and gas between an emitting astronomical object and the observation, observer. Interstellar extinction was first documented as such in 1930 by Robert Julius Trumpler. However, its effects had been noted in 1847 by Friedrich Georg Wilhelm von Struve, and its effect on the colors of stars had been observed by a number of individuals who did not connect it with the general presence of Cosmic dust, galactic dust. For stars lying near the plane of the Milky Way which are within a few thousand parsecs of the Earth, extinction in the visual band of frequencies (photometric system) is roughly 1.8 Magnitude (astronomy), magnitudes per kiloparsec. For Observatory#Ground-based_observatories, Earth-bound observers, extinction arises both from the interstellar medium and the Atmosphere of Earth, Earth's atmosphere; it may also arise fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comet
A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding the nucleus, and sometimes a Comet tail, tail of gas and dust gas blown out from the coma. These phenomena are due to the effects of solar radiation and the outstreaming solar wind plasma acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently close and bright, a comet may be seen from Earth without the aid of a telescope and can Subtended angle, subtend an arc of up to 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures and religion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Wisconsin-Madison
A university () is an institution of tertiary education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase , which roughly means "community of teachers and scholars". Universities typically offer both undergraduate and postgraduate programs. The first universities in Europe were established by Catholic monks. The University of Bologna (), Italy, which was founded in 1088, is the first university in the sense of: *being a high degree-awarding institute. *using the word (which was coined at its foundation). *having independence from the ecclesiastic schools and issuing secular as well as non-secular degrees (with teaching conducted by both clergy and non-clergy): grammar, rhetoric, logic, theology, canon law and notarial law.Hunt Janin: "The university in medieval life, 1179–1499", McFarland, 2008, , p. 55f.de Ridder-Symoens, Hilde''A History of the University in Europe: Volume 1, Universities in the M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur Code
Arthur Dodd Code (August 13, 1923 – March 11, 2009) was an astronomer who designed orbiting observatories. Code served as an electronics technician in the Navy during World War II. Arthur Code was born in Brooklyn, N.Y., and developed an early interest in astronomy when he was young. After military service, Code received a master's degree and doctorate in astronomy and astrophysics from the University of Chicago (without having received a bachelor's degree) advised by Subrahmanyan Chandrasekhar. He spent the majority of his career at the University of Wisconsin, where he was also director of the Washburn Observatory. He had previously taught at the University of Virginia and the California Institute of Technology. Code was one of the leaders of the OAO-2 project, an orbiting satellite that had light sensors, spectrometers, and various other radiation detectors. Data from OAO-2 demonstrated that young stars were hotter than previously believed, and also showed the existence of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passband
A passband is the range of frequency, frequencies or wavelengths that can pass through a Filter (signal processing), filter. For example, a radio receiver contains a bandpass filter to select the frequency of the desired radio signal out of all the radio waves picked up by its antenna. The passband of a receiver is the range of frequencies it can receive when it is tuned into the desired frequency as in a radio station or television channel. A band-pass filter, bandpass-filtered signal (that is, a signal with energy only in a passband), is known as a bandpass signal, in contrast to a baseband signal. The bandpass filter usually has two stopband, band-stop filters. Filters In telecommunications, optics, and acoustics, a passband (a band-pass filtered signal) is the portion of the frequency spectrum that is transmitted (with minimum relative loss or maximum relative Gain (electronics), gain) by some filtering device. In other words, it is a ''band'' of frequencies which ''pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photocathode
A photocathode is a surface engineered to convert light (photons) into electrons using the photoelectric effect. Photocathodes are important in accelerator physics where they are utilised in a photoinjector to generate high brightness electron beams. Electron beams generated with photocathodes are commonly used for free electron lasers and for ultrafast electron diffraction. Photocathodes are also commonly used as the negatively charged electrode in a light detection device such as a photomultiplier, phototube and image intensifier. Important Properties Quantum Efficiency (QE) Quantum efficiency is a unitless number that measures the sensitivity of the photocathode to light. It is the ratio of the number of electrons emitted to the number of incident photons. Rao, T., & Dowell, D. H. (2013). ''An engineering guide to photoinjectors''. CreateSpace Independent Publishing. This property depends on the wavelength of light being used to illuminate the photocathode. For man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
