European Southern Observatory

European Southern Observatory

The oldest observatory, inaugurated in 1969, is located on Cerro La Silla at an altitude of about 8,000 ft (2,400 m). The initial instrument was a 142-in. (3.6-m) reflecting telescope, but in 1989 the 141-in. (3.58-m) New Technology Telescope (NTT) was installed. Its primary mirror is three times faster than the original and has only half its weight. It uses a principle called active optics, in which the optics are adjusted by computer to react to the changing seeingseeing,
in astronomy, the clarity with which stars and other celestial objects can be observed. It is primarily determined by the atmosphere of the earth. The most obvious phenomenon is twinkling, when the brightness of a star seems to fluctuate.
..... Click the link for more information.  conditions of the night sky. Other instruments include a 86.6-in. (2.2-m) reflector, a 20-in. (0.5-m) reflector, a 39.4-in. (1-m) Schmidt camera telescope, twin 15.7-in. (0.4-m) astrographic telescopes, a 60-in. (1.52-m) spectrographic reflector, and a 39.4-in. (1-m) photometric reflector. Also located at Cerro La Silla are a 20-in. (0.5-m) reflector belonging to Denmark, a 23.5-in. (0.6 m) reflector used by the Univ. of Liège, Belgium, and the Univ. of Geneva, Switzerland, to search for exoplanets and comets, and a 24.4-in. (0.62-m) reflector belonging to the Univ. of Bochum, Germany.

The second observatory, initiated in 1988 and inaugurated in 1999, is located atop Cerro Paranal at an altitude of about 8,640 ft (2,635 m). The observatory is the home of the Very Large Telescope (VLT) program. Begun in 1996, it links four 315-in. (8-m) telescopes, usually in groups of two or three, together with several movable 72-in. (1.8-m) telescopes through optical interferometry, a technique in which the signals from each telescope enhance the signals from the others. Completed in 2003, the combination produces a virtual telescopevirtual telescope,
a computerized interferometer (see interference) that merges the images from two or more telescopes to obtain a single, large, enhanced image. The image in each telescope is made from electromagnetic waves (light waves from an optical telescope, radio waves
..... Click the link for more information.  image that is up to 25 times more detailed than an image produced by one of the individual telescopes. Also there is the Visible and Infrared Survey Telescope for Astronomy (VISTA), which was constructed by a British university consortium and officially handed over to the ESO in 2009. VISTA is 13-ft (4-m) wide-field survey telescope and is equipped with a near infrared camera.

ESO's newest site is Chajnantor, located at an altitude of some 16,730 ft (5,100 m), where ESO, the National Radio Astronomy ObservatoryNational Radio Astronomy Observatory
(NRAO), federal observatory for radio astronomy, founded in 1956 and operated under contract with the National Science Foundation by Associated Universities, Inc., a group of major universities. The headquarters are at Charlottesville, Va.
..... Click the link for more information. , the National Astronomical Observatory of Japan, and other partners broke ground for the Atacama Large Millimeter/Submillimeter Array (ALMA) in 2003. It began operations in 2011, and when completed will consist of an array of 66 39-ft (12-m) and 23-ft (7-m) radio telescopes. Also there is the APEX (Atacama Pathfinder Experiment) telescope, a 39-ft (12-m) submilliter radio telescope that is a collaboration among the Max Planck Institute for Radioastronomy, Onsala Space Observatory, and the ESO. It began operations in 2005.

Among the other programs of the observatory is the completion of the photographic Sky Survey for the Southern Hemisphere, in cooperation with the Siding Spring Observatory in Australia. This project is a continuation of the work begun in the Northern Hemisphere with the Schmidt telescope at Palomar Observatory.

European Southern Observatory

The chief instruments at La Silla are the 3.5-meter New Technology Telescope (NTT), which began operating in 1989, and the older 3.6-meter telescope, sometimes referred to as the ‘360’, which started operations in 1977. The 3.6-meter telescope works at focal ratios of f/3, f/8, and f/32 at the prime, Cassegrain, and coudé foci, and f/35 for infrared work. The limiting magnitude is 24 or more. The NTT has even better resolution than the 1 arcsec of the 3.6-meter and was a pioneer in the use of active optics. The 3.6-meter was upgraded in 1996 with an improved adaptive optics system. There is also a 2.2-meter telescope, installed in 1983, which is identical to the one at Calar Alto, Spain; a 1-meter Schmidt telescope, operational since 1972 and involved in the Southern Sky Survey; and four telescopes of 1 to 1.5 meters. The 15-meter Sweden–ESO Submillimeter Telescope became operational in 1989.

The ESO's Very Large Telescope (VLT), completed in 2001, is sited at Cerro Paranal, Chile. The VLT is the ESO's premier site for optical and infrared observations.