Astronomical survey

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 or spectra 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 catalog.

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 or her hypothesis, he or she is more likely to be given a chance to make more detailed observations.