Description: An astronomical survey is a collection of astronomical data obtained through observations of the whole of, or a region of, the sky. These surveys often contain information on the positions of the astronomical objects they catalog at a particular point in time as well as their brightnesses, colors, and other properties. Large astronomical surveys map the sky to both provide data for astronomical research and to help select targets for large telescopes.

The design of an astronomical survey will depend on its scientific objectives, for example aiming at the whole sky, large parts of the sky, or in smaller areas only. Surveys covering small areas or "pencil-beam" surveys can concentrate more time observing one part of the sky and thus can detect fainter objects than some wider surveys.

Astronomical surveys may cover specific parts of the electromagnetic spectrum such as radio waves or the infrared, or may combine data from different wavelength ranges.

Some astronomical surveys make repeated observations of the same part of the sky allowing the scientific study of the movement of objects across the sky and of the change in brightness of astronomical objects or the appearance of transient objects such as supernovae. By measuring the yearly change in the positions, astronomers can also calculate the distance of the objects using parallax. Another type of astronomical survey is a spectroscopy survey that measures the spectra of thousands (or millions) of stars, galaxies, and other astronomical objects.

Related Terms:

• Brightness
• Color
• Infrared Astronomy
• Optical Astronomy
• Parallax
• Radio Astronomy
• Sky Map
• Spectrum
• Supernova

Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".