The scene spans from east, at left, to southeast. It combines four pointings of the rover's panoramic camera (Pancam) on March 13, 2015, during the 3,958th Martian day, or sol, of Opportunity's work on Mars.
The rover team selected Marathon Valley as a science destination because observations of this location using the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on NASA's Mars Reconnaissance Orbiter yielded evidence of clay minerals, a clue to ancient wet environments. By the time Opportunity explores Marathon Valley, the rover will have exceeded a total driving distance equivalent to an Olympic marathon. Opportunity has been exploring the Meridiani Planum region of Mars since January 2004.
This version of the image is presented in approximate true color by combining exposures taken through three of the Pancam's color filters at each of the four camera pointings, using filters centered on wavelengths of 753 nanometers (near-infrared), 535 nanometers (green) and 432 nanometers (violet).
Image Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ. via NASA http://ift.tt/1Iqoes9 Amazing.