Hubble Space Telescope


Hubble Space Telescope

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 the most sophisticated optical observatory ever placed into orbit around Earth. Earth's atmosphere obscures ground-based astronomers' view of celestial objects by absorbing or distorting light rays from them. A telescope stationed in outer space is entirely above the atmosphere, however, and receives images of much greater brightness, clarity, and detail than do ground-based telescopes with comparable optics.

 After the U.S. Congress had authorized its construction in 1977, the Hubble Space Telescope was built under the supervision of the National Aeronautics and Space Administration (NASA) of the United States and was named after Edwin Hubble (Hubble, Edwin Powell), the foremost American astronomer of the 20th century. The HST was placed into orbit about 600 km (370 miles) above Earth by the crew of the space shuttle Discovery on April 25, 1990.

 The HST is a large reflecting telescope whose mirror optics gather light from celestial objects and direct it into two cameras and two spectrographs. The HST has a 2.4-metre (94-inch) primary mirror, a smaller secondary mirror, and various recording instruments that can detect visible, ultraviolet (ultraviolet radiation), and infrared light (infrared radiation). The most important of these instruments, the wide-field planetary camera, can take either wide-field or high-resolution images of the planets (planet) and of galactic and extragalactic objects. This camera is designed to achieve image resolutions 10 times greater than that of even the largest Earth-based telescope. A faint-object camera can detect an object 50 times fainter than anything observable by any ground-based telescope; a faint-object spectrograph gathers data on the object's chemical composition. A high-resolution spectrograph receives distant objects' ultraviolet light that cannot reach Earth because of atmospheric absorption.

 About one month after launch, it became apparent that the HST's large primary mirror had been ground to the wrong shape owing to faulty testing procedures by the mirror's manufacturer. The resulting optical defect, spherical aberration, caused the mirror to produce fuzzy rather than sharp images. The HST also developed problems with its gyroscopes (gyroscope) and with its solar-power arrays. On Dec. 2–13, 1993, a mission of the NASA space shuttle Endeavour sought to correct the telescope's optical system and other problems. In five space walks, the shuttle astronauts replaced the HST's wide-field planetary camera and installed a new device containing 10 tiny mirrors to correct the light paths from the primary mirror to the other three scientific instruments. The mission proved an unqualified success, and the HST soon began operating at its full potential, returning spectacular photographs of various cosmic phenomena.

 Three subsequent space shuttle missions in 1997, 1999, and 2002 repaired the HST's gyroscopes and added new instruments including a near-infrared spectrometer and a wide-field camera. The final space shuttle mission to service the HST, intended to install a new camera and an ultraviolet spectrograph, was scheduled for 2009. The HST is scheduled to remain operational until 2013, when it is expected to be replaced by the James Webb Space Telescope, equipped with a mirror seven times larger than that of the HST.

      The HST's discoveries have revolutionized astronomy. Observations of Cepheid variables (Cepheid variable) in nearby galaxies (galaxy) allowed the first accurate determination of Hubble's constant, which is the rate of the universe's expansion. The HST photographed young stars (star) with disks that will eventually become planetary systems. The Hubble Deep Field, a photograph of about 1,500 galaxies, revealed galactic evolution over nearly the entire history of the universe.

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Universalium. 2010.

Look at other dictionaries:

  • Hubble-Space-Telescope — Hubble Weltraumteleskop, aufgenommen von der STS 82 Mission Das Hubble Weltraumteleskop (engl. Hubble Space Telescope, kurz HST) ist ein Weltraumteleskop für sichtbares Licht, Ultraviolett und Infrarotstrahlung, das die Erde in 590 Kilometer Höhe …   Deutsch Wikipedia

  • Hubble Space Telescope — Hubble Weltraumteleskop, aufgenommen von der STS 82 Mission Das Hubble Weltraumteleskop (engl. Hubble Space Telescope, kurz HST) ist ein Weltraumteleskop für sichtbares Licht, Ultraviolett und Infrarotstrahlung, das die Erde in 590 Kilometer Höhe …   Deutsch Wikipedia

  • Hubble Space Telescope — Hubble (télescope spatial) Pour les articles homonymes, voir Hubble. Télescope spatial Hubble …   Wikipédia en Français

  • Hubble Space Telescope — Hubble Telescope Hub ble Tel e*scope, Hubble Space Telescope Hub ble Space Tel e*scope, n. A large astromical optical telescope placed into orbit around the earth, from which, in the absence of absorption and distortion by the earth s atmosphere …   The Collaborative International Dictionary of English

  • Hubble Space Telescope — Infobox Space telescope name = Hubble Space Telescope (HST) caption = The Hubble Space Telescope as seen from Space Shuttle Discovery during its second servicing mission (STS 82) organization = NASAESASTScI alt names = nssdc id =… …   Wikipedia

  • Hubble Space Telescope — Aerospace. See Space Telescope …   Useful english dictionary

  • Hubble Space Telescope — /ˈhʌbəl/ (say hubuhl) noun a US space observatory containing a reflector telescope, launched into orbit in 1990. Abbrev.: HST {See Hubble s constant} …   Australian English dictionary

  • Hubble Space Telescope — powerful telescope that was launched into space by the United States in 1990 and transmits magnified photographs of galaxies and objects in space …   English contemporary dictionary

  • Hubble Space Telescope — Hub′ble Space′ Tel escope n. ars an orbiting astronomical observatory launched in 1990, designed to observe extremely distant space from its orbit 370 mi. (592 km) above the earth s atmosphere …   From formal English to slang

  • Hubble Space Telescope (HST) — Most sophisticated optical observatory ever placed into orbit around Earth. Because it is above Earth s obscuring atmosphere, it can obtain images much brighter, clearer, and more detailed than ground based telescopes can. Named for Edwin Hubble …   Universalium


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