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Palomar Testbed Interferometer
The Palomar Testbed Interferometer (PTI) was a near infrared, long-baseline stellar interferometer located at Palomar Observatory in north San Diego County, California, United States. It was built by Caltech and the Jet Propulsion Laboratory and was intended to serve as a testbed for developing interferometric techniques to be used at the Keck Interferometer. It began operations in 1995 and achieved routine operations in 1998, producing more than 50 refereed papers in a variety of scientific journals covering topics from high precision astrometry to stellar masses, stellar diameters and shapes. PTI concluded operations in 2008 and has since been dismantled. PTI was notable for being equipped with a "dual-star" system, making it possible to simultaneously observe pairs of stars; this cancels some of the atmospheric effects of astronomical seeing and makes very high precision measurements possible. A groundbreaking study with the Palomar Testbed Interferometer revealed that the st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palomar Mountain
Palomar Mountain ( ; ) is a mountain ridge in the Peninsular Ranges in northern San Diego County, California. It is known as the location of Palomar Observatory and Hale Telescope, and known for Palomar Mountain State Park. History The Luiseño name for Palomar Mountain was and High Point was called . The Spanish name ''Palomar'', meaning "pigeon roost" or "place of the pigeons", comes from the Spanish colonial era in Alta California when Palomar Mountain was known as the home of band-tailed pigeons. The peak was once called Mount Joseph Smith but reverted to its Spanish name, Palomar, in 1901. During the 1890s, the population was sufficient to support three public schools, and it was a popular summer resort for Southern California, with three hotels in operation part of the time, and a tent city in Doane Valley each summer. Nathan Harrison, the first African American homesteader in San Diego area, purchased several acres on the western slope of the mountain in the 1880s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near Infrared
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of red light (the longest waves in the visible spectrum), so IR is invisible to the human eye. IR is generally (according to ISO, CIE) understood to include wavelengths from around to . IR is commonly divided between longer-wavelength thermal IR, emitted from terrestrial sources, and shorter-wavelength IR or near-IR, part of the solar spectrum. Longer IR wavelengths (30–100 μm) are sometimes included as part of the terahertz radiation band. Almost all black-body radiation from objects near room temperature is in the IR band. As a form of EMR, IR carries 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 invis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interferometer
Interferometry is a technique which uses the '' interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber optics, engineering metrology, optical metrology, oceanography, seismology, spectroscopy (and its applications to chemistry), quantum mechanics, nuclear and particle physics, plasma physics, biomolecular interactions, surface profiling, microfluidics, mechanical stress/strain measurement, velocimetry, optometry, and making holograms. Interferometers are devices that extract information from interference. They are widely used in science and industry for the measurement of microscopic displacements, refractive index changes and surface irregularities. In the case with most interferometers, light from a single source is split into two beams that travel in different optical paths, which are then combined again to produce interference; two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palomar Observatory
The Palomar Observatory is an astronomical research observatory in the Palomar Mountains of San Diego County, California, United States. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observatory is granted to Caltech and its research partners, which include the Jet Propulsion Laboratory (JPL), Yale University, and the National Astronomical Observatories of China. The observatory operates several telescopes, including the Hale Telescope, the Samuel Oschin telescope (dedicated to the Zwicky Transient Facility, ZTF),) the Palomar Telescope, and the Gattini-IR telescope. Decommissioned instruments include the Palomar Testbed Interferometer and the first telescopes at the observatory, an Schmidt camera from 1936. History Hale's vision for large telescopes and Palomar Observatory Astronomer George Ellery Hale, whose vision created Palomar Observatory, built the world's largest telescope four times in succession. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Diego County
San Diego County (), officially the County of San Diego, is a county in the southwest corner of the U.S. state of California, north to its border with Mexico. As of the 2020 census, the population was 3,298,634; it is the second-most populous county in California and the fifth-most populous in the United States. Its county seat is San Diego, the second-most populous city in California and the eighth-most populous in the United States. It is the southwesternmost county in the 48 contiguous United States, and is a border county. It is home to 18 Indian reservations, the most of any county in the United States. There are 16 military installations of the U.S. Navy, Marine Corps, and Coast Guard in the county. San Diego County comprises the San Diego–Chula Vista–Carlsbad, CA Metropolitan Statistical Area, which is the 17th most populous metropolitan statistical area and the 18th most populous primary statistical area in the United States. San Diego County is also part o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caltech
The California Institute of Technology (branded as Caltech) is a private university, private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of Institute of Technology (United States), institutes of technology in the United States that are devoted to the instruction of pure and applied sciences. The institution was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began attracting influential scientists such as George Ellery Hale, Arthur Amos Noyes, and Robert Andrews Millikan in the early 20th century. The vocational and preparatory schools were disbanded and spun off in 1910, and the college assumed its present name in 1920. In 1934, Caltech was elected to the Association of American Universities, and the antecedents of NASA's Jet Propulsion Laboratory, which Caltech continues to manage and operate, were established between 1936 and 1943 under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Propulsion Laboratory
The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by California Institute of Technology (Caltech) researchers, the laboratory is now owned and sponsored by NASA and administered and managed by Caltech. The primary function of the laboratory is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating the NASA Deep Space Network (DSN). Among the major active projects at the laboratory, some are the Mars 2020 mission, which includes the ''Perseverance (rover), Perseverance'' rover; the Mars Science Laboratory mission, including the ''Curiosity (rover), Curiosity'' rover; the ''Mars Reconnaissance Orbiter''; the ''Juno (spacecraft), Juno'' spacecraft orbiting Jupiter; the ''Soil Moisture Active P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keck Interferometer
The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes have aperture primary mirrors, and, when completed in 1993 (Keck I) and 1996 (Keck II), they were the List of largest optical reflecting telescopes, largest optical reflecting telescopes in the world. They have been the third and fourth largest since 2006. Overview With a concept first proposed in 1977, telescope designers Terry Mast, of the University of California, Berkeley, and Jerry Nelson (astronomer), Jerry Nelson of Lawrence Berkeley Laboratory had been developing the technology necessary to build a large, ground-based telescope. In 1985, Howard B. Keck of the W. M. Keck Foundation gave $70 million to fund the construction of the Keck I telescope, which began in September 1985. First light occurred on November 24, 1990, using 9 of the eventual 36 segments. When const ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrometry
Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other Astronomical object, celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way. History The history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements. This can be dated back to the ancient Greek astronomer Hipparchus, who around 190 BC used the catalogue of his predecessors Timocharis and Aristillus to discover Earth's precession. In doing so, he also developed the brightness scale still in use today. Hipparchus compiled a catalogue with at least 850 stars and their positions. Hipparchus's successor, Ptolemy, included a catalogue of 1,022 stars in his work the ''Almagest'', giving their location, coordinates, and brightness. In the 10th century, the Iranian astronomer Abd al-Rahman al-Sufi carried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal in astronomy, astrophysics and related fields. It publishes original research in two formats: papers (of any length) and letters (limited to five pages). MNRAS publishes more articles per year than any other astronomy journal. The learned society journal has been in continuous existence since 1827 and became online only in 2020. It operates as a partnership between the Royal Astronomical Society (RAS), who select and peer-review the contents, and Oxford University Press (OUP), who publish and market the journal. Despite its name, MNRAS is no longer monthly, nor does it carry the notices of the RAS. In 2024 MNRAS became a purely gold open access journal. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Seeing
In astronomy, seeing is the degradation of the real image, image of an astronomical object due to turbulence in the atmosphere of Earth that may become visible as blurring, twinkling or variable Distortion (optics), distortion. The origin of this effect is rapidly changing variations of the optical refractive index along the light path from the object to the detector. Seeing is a major limitation to the angular resolution in astronomical observations with telescopes that would otherwise be Angular resolution#The Rayleigh criterion, limited through diffraction by the size of the telescope aperture. Today, many large scientific ground-based optical telescopes include adaptive optics to overcome seeing. The strength of seeing is often characterized by the angular diameter of the long-exposure image of a star (''seeing disk'') or by the Fried parameter ''r''0. The diameter of the seeing disk is the full width at half maximum of its optical intensity. An exposure time of several tens o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altair
Altair is the brightest star in the constellation of Aquila (constellation), Aquila and the list of brightest stars, twelfth-brightest star in the night sky. It has the Bayer designation Alpha Aquilae, which is Latinisation of names, Latinised from α Aquilae and abbreviated Alpha Aql or α Aql. Altair is an A-type main-sequence star, A-type main-sequence star with an apparent visual magnitude of 0.77 and is one of the vertices of the Summer Triangle Asterism (astronomy), asterism; the other two vertices are marked by Deneb and Vega. It is located at a distance of from the Sun. Altair is currently in the G-cloud—a nearby interstellar cloud formed from an accumulation of gas and dust. Altair rotates rapidly, with a velocity at the equator of approximately 286 km/s.From values of ''v'' sin ''i'' and ''i'' in the second column of Table 1, Monnier et al. 2007. This is a significant fraction of the star's estimated breakup speed of 400 km/s. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
