An astronomical survey is a general map or image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of objects that 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.
4-573: The Deep Near Infrared Survey of the Southern Sky ( DENIS ) was a deep astronomical survey of the southern sky in the near-infrared and optical wavelengths, using an ESO 1-metre telescope at the La Silla Observatory . It operated from 1996 to 2001. This astronomical catalog article is a stub . You can help Misplaced Pages by expanding it . Astronomical survey Surveys have generally been performed as part of
8-495: A hypothesis, a telescope scheduling committee is more likely to approve new, more detailed observations to test it. The wide scope of surveys makes them ideal for finding foreground objects that move, such as asteroids and comets. An astronomer can compare existing survey images to current observations to identify changes; this task can even be performed automatically using image analysis software. Besides science, these surveys also detect potentially hazardous objects , providing
12-587: A service to Spaceguard . For example, the Asteroid Terrestrial-impact Last Alert System (ATLAS) system surveys the entire night sky every night and, like NEOSTEL , is intended to detect objects as they approach. Broader surveys include the Uppsala–DLR Asteroid Survey and the 20th-century U.K. Schmidt–Caltech Asteroid Survey . Old surveys can be reviewed to find precovery images. Similarly, images of
16-643: The production of an astronomical catalog . They may also search for transient astronomical events . They often use wide-field astrographs . Sky surveys, unlike targeted observation of a specific object, allow astronomers to catalog celestial objects and perform statistical analyses on them without complex corrections for selection effects . In some cases, an astronomer interested in a particular object will find that survey images are sufficient to make new telescope time entirely unnecessary. Surveys also help astronomers choose targets for closer study using larger, more powerful telescopes. If previous observations support
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