Copernicus is a rayed crater, 97 kilometers in diameter, that formed about 900 million years ago. In this image of the crater Copernicus, color differences are shown for the eastern half of the crater. A false-color mosaic is created by making ratio images and assigning each to one of the three primary colors: The red channel is controlled by the 750/415-nanometer ratio, the green channel is controlled by the 750/950-nanometer ratio, and the blue channel is controlled by the 415/750-nanometer ratio. The diversity of color in the crater deposits indicates a complex geological structure, composed of many different rock types.
Image processing by Brown University, Providence, Rhode Island.