An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A building, place, or institution designed and equipped for making → observations of astronomical phenomena.

→ astronomical; → observatory.

A complex of astronomical telescopes and instruments located approximately 80 km to the East of La Serena, Chile, at an altitude of 2,200 m. CTIO headquarters are located in La Serena, Chile, about 480 km north of Santiago. The principal telescopes on site are the 4-m Victor M. Blanco Telescope and the 4.1-m Southern Astrophysical Research (SOAR) telescope. One of the two 8-m telescopes comprising the Gemini Observatory is co-located with CTIO on the Association of Universities for Research in Astronomy (AURA) property in Chile, together with more than 10 other telescopes and astronomical projects.

Cerro "mountain" in Spanish; Tololo a proper name; → inter-; American, from America, → North America Nebula; → Observatory.

A high plateau site located at an altitude of 5,104 m in the Chilean Atacama desert, about 50 kilometers to the east of San Pedro de Atacama (longitude 67° 46' W, latitude 23° 02' S). It is the site of the → Atacama Large Millimeter Array.

In Kunza, the ancestral language of the people living in the region, Chajnantor or Tchacknatur means "lift-off place." It is the place of platforms for worshipping the Sun, where since immemorial time prayers and wishes lifted off (ESO book Cerca del Cielo).

An astronomy satellite launched by NASA in 1999 July, specially designed to detect X-ray emission from very hot regions of the Universe such as exploded stars, clusters of galaxies, and matter around black holes. Chandra carries a high resolution mirror (aperture 1.2 m, focal length 10 m), two imaging detectors (HRC and ACIS), and two sets of transmission grating spectrometer (LETG and HETG). Important Chandra features are: an order of magnitude improvement in spatial resolution, good sensitivity from 0.1 to 10 keV, and the capability for high spectral resolution observations over most of this range. Chandra was initially given an expected lifetime of 5 years, but on 4 September 2001 NASA extended its lifetime to 10 years "based on the observatory's outstanding results." Among the results obtained using Chandra one can mention the spectacular image of the → supernova remnant Cassiopeia A. See also → X-ray astronomy.

Initially called Advanced X-ray Astrophysics Facility (AXAF), the satellite was renamed the Chandra X-ray Observatory in honor of Subrahmanyan Chandrasekhar, the 1983 Nobel Prize in Physics, → Chandrasekhar limit. Moreover, Chandra, or candra- means "moon" or "shining" in Skt., from cand- "to give light, shine;" cf. Gk. kandaros "coal;" L. candela "a light, torch," from candere "to shine;" → X-ray; → Observatory.

An major intergovernmental research organisation in astronomy supported by 14 European countries. ESO was founded in 1962 as a consortium among Belgium, Denmark, France, Germany, the Netherlands, and Sweden. The ESO Headquarters are located in Garching near Munich, Germany. The organization operates three outstanding observing sites in the Atacama Desert region of Chile: → La Silla, → Paranal, and Chajnantor. The → Very Large Telescope (VLT), the world's most advanced visible-light astronomical facility, is located on the 2600 m high mountain of Paranal, which also hosts the → VLT Interferometer (VLTI). The Chajnantor site, 5000 m above sea level, near San Pedro de Atacama, operates a submillimeter telescope (APEX). Moreover, a giant array of 12 m submillimeter antennas, called → ALMA, is being constructed in collaboration with North America, East Asia and Chile. ESO is currently planning a 42 m European Extremely Large optical/near-infrared Telescope, the → E-ELT.

→ European; → southern; → observatory.

An observation which expands previous observations and aims at obtaining complementary data in particular with other telescopes/instruments.

Follow-up, from follow, from O.E. folgian, fylgan "to follow, pursue," from W.Gmc. *fulg- (cf. O.Fris. folgia, M.Du. volghen, Ger. folgen "to follow") + up, O.E. up, uppe (cf. Du. op, Ger. auf "up, upward"), from PIE base *upo "up from below;" cf. O.Pers./Av. upā; Skt. úpa; Gk. hypo; L. sub, → hypo-; → observation.

Nepâheš, → observation; peygir, from pey "after; step," related to pâ "foot, step, track," → foot, + gir present stem of gereftan "to take, seize" (Mid.Pers. griftan, Av./O.Pers. grab- "to take, seize," cf. Skt. grah-, grabh- "to seize, take," graha "seizing, holding, perceiving," M.L.G. grabben "to grab," from P.Gmc. *grab, E. grab "to take or grasp suddenly;" PIE base *ghrebh- "to seize").

An astronomical observation carried out using a telescope on Earth, as opposed to that from an orbiting satellite.

→ ground; based, adj. of base, from O.Fr. bas, from L. basis "foundation," from Gk. basis "step, pedestal," from bainein "to step;" → observation.

Nepâheš, → observation; az "from," → ex-; zamin, → ground.

An observation that provides a particularly narrow, peaked image of a point source. → point spread function.

→ high; → resolution; → observation.

A European Space Agency satellite which carried the most sensitive infrared telescope ever launched. It operated between November 1995 and April 1998 and made particularly important observations of the dusty regions of the Universe. ISO was equipped with four science instruments: an infrared camera (CAM), a long-wavelength spectrometer (LWS), a photo-polarimeter (PHT), and a short-wavelength spectrometer (SWS). The instruments jointly covered wavelengths from 2.5 to around 240 microns with spatial resolutions ranging from 1.5 arcseconds to 90 arcseconds. Its 60 cm diameter telescope was cooled by superfluid liquid helium to temperatures of 2-4 K. The mission was a great technical, operational and scientific success. During its routine operational phase, ISO successfully made some 30,000 individual imaging, photometric, spectroscopic, and polarimetric observations ranging from objects in our own solar system to the most distant extragalactic sources.

→ infrared; → space; → observatory.

An international cooperation whose objective is to facilitate the international coordination and collaboration necessary for the development and deployment of the tools, systems and organizational structures necessary to enable the international utilization of astronomical archives as an integrated and interoperating → Virtual Observatory. The IVOA, created in 2002, now comprises 20 Virtual Observatory programs from various countries and international organizations.

→ international; → virtual; → observatory; → alliance.

The site of the → European Southern Observatory's first observatory in Chile, inaugurated in 1969. It is located 160 km north of the town of La Serena and 600 km north of Santiago at an altitude of 2,400 m bordering the southern extremity of the Atacama Desert. La Silla is equipped with several optical telescopes with mirror diameters of up to 3.6 m. The 3.5 m New Technology Telescope was the first in the world to have a computer-controlled main mirror, a technology developed at ESO. The ESO 3.6 m telescope is now home to the world's largest extrasolar planet hunter: HARPS (High Accuracy Radial velocity Planet Searcher), a spectrograph with unrivalled precision.

From Sp. la silla "the saddle," after the apparent shape of the mountain on which the observatory is situated. Originally known as Cinchado.

A facility dedicated to the detection and measurement of cosmic → gravitational waves. It consists of two widely separated installations, or detectors, within the United States, operated in unison as a single observatory. One installation is located in Hanford (Washington) and the other in Livingston (Louisiana), 3,000 km apart. Funded by the National Science Foundation (NSF), LIGO was designed and constructed by a team of scientists from the California Institute of Technology, the Massachusetts Institute of Technology, and by industrial contractors. Construction of the facilities was completed in 1999. Initial operation of the detectors began in 2001. Each LIGO detector beams laser light down arms 4 km long, which are arranged in the shape of an "L." If a gravitational wave passes through the detector system, the distance traveled by the laser beam changes by a minuscule amount -- less than one-thousandth of the size of an atomic nucleus (10^-18 m). Still, LIGO should be able to pick this difference up. LIGO directly detected gravitational waves for the first time from a binary → black hole merger (GW150914) on September 14, 2015 (Abbott et al., 2016, Phys. Rev. Lett. 116, 061102). The Nobel Prize in physics 2017 was awarded to three physicists (Rainer Weiss, Barry C. Barish, and Kip S. Thorne) for decisive contributions to the LIGO detector and the observation of gravitational waves. LIGO had a prominent role in the detection of → GW170817, the first event with an → electromagnetic counterpart.

→ laser; → interferometer; → gravitational; → wave; → observatory.

The observation of a star when it crosses an observer's meridian.

→ meridian; → observation.

Evaluation or measurement of one or more meteorological elements.

Meteorological, of or pertaining to → meteorology; → observation.

A scientific establishment dedicated to making precise and detailed meteorological observations and to studying and forecasting atmospheric phenomena by means of special equipments.

Meteorological, of or pertaining to → meteorology; → observatory.

An observatory situated on a mountain 1700 m above sea level near Pasadena, California. It was built in 1904 by American astronomer George Ellery Hale as a solar-observing station for the Yerkes Observatory, but it became an independent observatory funded by the Carnegie Institution of Washington. In 1908 a 60-inch (152-cm) reflector, then the largest in the world, was added for observations of stars and galaxies. Ten years later a 100-inch (254-cm) reflecting telescope was put into service. It was the most powerful telescope in the world until the construction of the Palomar 200-inch reflector in 1948. The 100-inch telescope's most important discovery was Edwin Hubble's determination of the distance to the Andromeda Nebula in 1924. He showed that the nebula lay beyond the bounds of the Milky Way Galaxy and hence was a galaxy in its own right. Then in 1929, following the work of Vesto Slipher, Hubble and his assistant Milton Humason demonstrated that galaxies were moving away from one another. This movement is the expansion of the Universe.

→ mountain; a peak of the San Gabriel Mountains, located in northern Los Angeles County, California, named after Benjamin D. Wilson (1811-1878) a California statesman and politician; → observatory .

1) General: The character of something that can be observed.
2) Astro.: The possibility that an object be observable at a particular time.
3) Control theory: A measure for how well internal states of a system can be inferred by knowledge of its external outputs.

From → observable + → -ity.

1) Capable of being or liable to be observed.
2) A quantity that can be measured.
3) Quantum mechanics: A → real dynamical variable whose → eigenstates form a → complete set.

From → observe + → -able.

The extent of the Universe that we can see with the aid of the largest telescopes. Its ultimate boundary is determined by the → cosmic horizon size.

→ observable; → universe.

1) Act or instance of observing; → observe.
2) Careful watching of an astronomical object or event using appropriate instruments, usually for collecting data.

Verbal noun of → observe.