A "Sky Survey" is a systematic observation of the night sky to collect data about celestial objects. This process involves using telescopes and other instruments to capture images and measure the properties of stars, galaxies, and other astronomical phenomena. Sky surveys help astronomers map the universe and understand its structure and evolution. There are various types of sky surveys, such as the Sloan Digital Sky Survey and the Hubble Space Telescope observations. These surveys can be conducted in different wavelengths, including visible light, infrared, and radio, allowing scientists to study objects that may not be visible to the naked eye.