Charge-Coupled Device

Charge-coupled devices (CCDs) have made possible a revolution in image processing. They consist of a series of light-sensitive elements, called pixels, arranged in a square or rectangular array. When CCDs are exposed to light, an image of the object being observed is formed; this image can be extracted from the CCD and stored on a computer for later analysis. CCDs are used in a variety of modern instruments, ranging from scanners and photocopiers to video cameras and digital still cameras. They have transformed the way scientists measure and chart the universe. Because CCDs are available in a wide price range, they are accessible to amateurs as well as professionals, and enable both to make significant contributions to modern astronomy.