Astronomical surveys involve systematic observations of a large portion of the sky to gather data on celestial objects such as stars, galaxies, and other astronomical phenomena. These surveys typically use ground-based telescopes or space-based observatories to gather data over a wide range of wavelengths, from radio to gamma rays. The data collected from these surveys are used to study the distribution, properties, and evolution of celestial objects, as well as to search for new phenomena and objects in the universe. Astronomical surveys have played a critical role in advancing our understanding of the cosmos and continue to provide valuable insights into the nature of the universe.