This image of the Centauri-Hellas Montes region was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at a portion of a trough in the Nili Fossae region of Mars is shown in enhanced color in this image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. The Nili Fossae region has one of the largest exposures of clay minerals discovered by the mapping spectrometer (called OMEGA for its French name's acronym) on the European Space Agency's Mars Express orbiter. The scene is illuminated from the west with a solar incidence angle of 62 degrees, thus the sun was about 28 degrees above the horizon. The season on Mars was northern autumn. Credit: NASA/JPL-Caltech/Univ. of Arizona