Astronomical surveys
Overview
 
An astronomical survey is a general map or image of a region of the sky which lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of many images of objects which share a common type or feature. Surveys are often restricted to one band of the electromagnetic spectrum due to instrumental limitations, although multiwavelength surveys can be made by using multiple detectors, each sensitive to a different bandwidth.
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Encyclopedia
An astronomical survey is a general map or image of a region of the sky which lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of many images of objects which share a common type or feature. Surveys are often restricted to one band of the electromagnetic spectrum due to instrumental limitations, although multiwavelength surveys can be made by using multiple detectors, each sensitive to a different bandwidth. Surveys have generally been performed as part of the
production of an astronomical catalogue.

Scientific value

Sky surveys, unlike targeted observation of a specific object, allow astronomers to catalogue celestial objects and perform statistical analyses on them without making prohibitively lengthy observations. In some cases, an astronomer interested in a particular object will find that survey images are sufficient to entirely obviate the need for telescope time.

Surveys also help astronomers obtain observation time on larger, more powerful telescopes. If the astronomer can show a telescope scheduling committee that previous observations support his hypothesis, he is more likely to be given a chance to make more detailed observations.

The wide scope of surveys makes them ideal for astronomers searching for moving foreground objects such as asteroids and comets. An astronomer can compare existing survey images to current observations to locate targets which are in motion; this task can even be performed automatically using image analysis software. Similarly, images of the same object taken by different surveys can be compared to detect transient events such as variable stars.

List of sky surveys

  • Optical
    • Pan-Andromeda Archaeological Survey
      Pan-Andromeda Archaeological Survey
      Pan-Andromeda Archaeological Survey is a large-scale astronomical survey using the Canada-France-Hawaii Telescope.The survey is exploring the structure and content of the Andromeda Galaxy and its neighbour, the Triangulum Galaxy . Clues to the formation of these galaxies may lie within the vast...

    • National Geographic Society – Palomar Observatory Sky Survey
      National Geographic Society – Palomar Observatory Sky Survey
      The National Geographic Society – Palomar Observatory Sky Survey is a major photographic survey of the night sky that was completed at Palomar Observatory in 1958.-Observations:...

       (NGS–POSS) - survey of the northern sky on photographic plates, 1948–1958
    • Digitized Sky Survey
      Digitized Sky Survey
      The Digitized Sky Survey is a digital version of several photographic atlases of the night sky, and an ongoing project to produce more digital versions of photographic astronomical datasets.- Versions and source material :...

       - optical all-sky survey created from digitized photographic plates, 1994
    • Sloan Digital Sky Survey
      Sloan Digital Sky Survey
      The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project was named after the Alfred P...

       - an optical and spectroscopic survey, 2000-2006 (first pass)
    • Photopic Sky Survey - a survey with 37,440 individual exposures, 2010-2011.

  • Infrared
    • Infrared Astronomical Satellite
      IRAS
      The Infrared Astronomical Satellite was the first-ever space-based observatory to perform a survey of the entire sky at infrared wavelengths....

       did an all sky survey at 12, 25, 60, and 100 μm, 1983
    • The 2-micron All-Sky Survey
      2MASS
      Observations for the Two Micron All-Sky Survey began in 1997 and were completed in 2001 at two telescopes located one each in the northern and southern hemispheres to ensure coverage of the entire sky...

       (2MASS), a ground based all sky survey at J, H, and Ks bands (1.25, 1.65, and 2.17 μm) 1997-2001
    • Akari (Astro-F) a Japanese mid and far infrared all-sky survey satellite, 2006–2008
    • Wide-field Infrared Survey Explorer was launched in December 2009 to begin a survey of 99% of the sky at wavelengths of 3.3, 4.7, 12, and 23 μm. The telescope is over a thousand times as sensitive as previous infrared surveys. The initial survey, consisting of each sky position imaged at least eight times, was completed by July 2010.
    • SCUBA-2 All Sky Survey
      SCUBA-2 All Sky Survey
      The SCUBA-2 All-Sky Survey , is a major astronomical experiment using the James Clerk Maxwell Telescope in Hawaii. A team of around 50 astronomers from the United Kingdom, Canada, the United States, Netherlands, and Japan aim to map a huge swathe of the sky to find rare galaxies and stars being...


  • Radio
    • HIPASS
      HIPASS
      The HI Parkes All Sky Survey was an astronomical survey for neutral atomic hydrogen . Data was taken between 1997 and 2002 using the Parkes Observatory. HIPASS covered 71% of the sky and identified 5317 sources emitting HI's signature wavelength...

       - Radio survey, the first blind HI
      Hydrogen line
      The hydrogen line, 21 centimeter line or HI line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation is at the precise frequency of 1420.40575177 MHz, which is equivalent to the vacuum...

       survey to cover the entire southern sky. 1997-2002
    • Ohio Sky Survey
      Ohio Sky Survey
      The Ohio Sky Survey was an astronomical survey of extragalactic radio sources. Data were taken between 1965 and 1971 using the Big Ear radio telescope at the Ohio State University Radio Observatory , also known as the "Big Ear Radio Observatory "....

       - Over 19,000 radio sources at 1415 MHz. 1965-1973.
    • NVSS - Survey at 1.4 GHz mapping the sky north of -40 deg
    • FIRST - Survey to look for faint radio sources at twenty cms.(see http://sundog.stsci.edu/index.html )

  • Gamma-ray
    • Fermi Gamma-ray Space Telescope, formerly referred to as the "Gamma-ray Large Area Space Telescope (GLAST)." 2008–present; the goal for the telescope's lifetime is 10 years.

  • Multi-wavelength surveys
    • GAMA
      Galaxy And Mass Assembly survey
      The is a project to exploit the latest generation of ground-based wide-field survey facilities to study cosmology and galaxy formation and evolution. GAMA will bring together data from a number of world class instruments:* The Anglo-Australian Telescope ,...

       - the Galaxy And Mass Assembly survey (see http://gama-survey.org) combines data from a number of ground- and space-based observatories together with a large redshift survey
      Redshift survey
      In astronomy, a redshift survey, or galaxy survey, is a survey of a section of the sky to measure the redshift of astronomical objects. Using Hubble's law, the redshift can be used to calculate the distance of an object from Earth. By combining redshift with angular position data, a redshift...

      , performed at the Anglo-Australian Telescope
      Anglo-Australian Telescope
      The Anglo-Australian Telescope is a 3.9 m equatorially mounted telescope operated by the Australian Astronomical Observatory and situated at the Siding Spring Observatory, Australia at an altitude of a little over 1100 m...

      . The resulting dataset aims to be a comprehensive resource for studying the physics of the galaxy population and underlying mass structures in the recent universe.
    • GOODS
      Great Observatories Origins Deep Survey
      The Great Observatories Origins Deep Survey or GOODS is an astronomical survey combining deep observations from three of NASAs Great Observatories: the Hubble Space Telescope, the Spitzer Space Telescope and the Chandra X-ray Observatory along with data from other space-based telescopes, such as...

       - The Great Observatories Origins Deep Survey.
    • COSMOS - The Cosmic Evolution Survey

(The latter two surveys are joining together observations obtained from space with the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...

, the Spitzer Space Telescope
Spitzer Space Telescope
The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...

, the Chandra X-ray Observatory
Chandra X-ray Observatory
The Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999. It was named in honor of Indian-American physicist Subrahmanyan Chandrasekhar who is known for determining the maximum mass for white dwarfs. "Chandra" also means "moon" or "luminous" in Sanskrit.Chandra...

 and the XMM-Newton
XMM-Newton
The XMM-Newton is an orbiting X-ray observatory launched by ESA in December 1999 on a Ariane 5 rocket...

 satellite, with a large set of observations obtained with ground-based telescopes).
  • Planned
    • Pan-STARRS
      Pan-STARRS
      The Panoramic Survey Telescope and Rapid Response System is a planned array of astronomical cameras and telescopes and computing facility that will survey the sky on a continual basis, including accurate astrometry and photometry of detected objects...

       - a proposed 4-telescope large-field survey system to look for transient and variable sources
    • Large Synaptic Survey Telescope
      Large Synoptic Survey Telescope
      The Large Synoptic Survey Telescope is a planned wide-field "survey" reflecting telescope that will photograph the available sky every three nights. The LSST is currently in its design and development phase and will achieve engineering first light four years after construction starts...

       - a proposed very large telescope designed to repeatedly survey the whole sky that is visible from its location

Surveys of the Magellanic Clouds

  • The Magellanic Clouds Photometric Survey - UBVI (optical)
  • Deep Near Infrared Survey (DENIS) - near-IR
  • Surveying the Agents of a Galaxy's Evolution - a Spitzer Space Telescope
    Spitzer Space Telescope
    The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...

     legacy observation program of the LMC

Further information

  • See astronomical catalogue for a more detailed description of astronomical surveys and the production of astronomical catalogues
  • Redshift survey
    Redshift survey
    In astronomy, a redshift survey, or galaxy survey, is a survey of a section of the sky to measure the redshift of astronomical objects. Using Hubble's law, the redshift can be used to calculate the distance of an object from Earth. By combining redshift with angular position data, a redshift...

    s are astronomical surveys devoted to mapping the cosmos in three dimensions

:Category:astronomical catalogues -- List of astronomical catalogues on wikipedia
  • Astrograph
    Astrograph
    An astrograph is a telescope designed for the sole purpose of astrophotography. Astrographs are usually used in wide field surveys of the night sky as well as detection of objects such as asteroids, meteors, and comets.-Design:...

     for a type of instrument used in Astronomical surveys.
  • Timeline of astronomical maps, catalogs, and surveys
    Timeline of astronomical maps, catalogs, and surveys
    Timeline of astronomical maps, catalogs and surveys* ca. 1800 BC — Babylonian star catalog* ca. 350 BC — Shi Shen's star catalog has almost 800 entries* ca. 300 BC — star catalog of Timocharis of Alexandria...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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