The shadow of the Martian moon, Phobos, is captured here by the Mars Global Surveyor wide angle camera. Frequent solar eclipses are caused by the passage of Phobos between Mars and the Sun. The shadow of Phobos, the elliptical feature at the center of each frame, is seen as it was cast upon western Xanthe Terra. Martian eclipses are thousands of times more common than eclipses on Earth, occurring a few times a day whenever Phobos passes over the planet's sunlit side. From left to right, the three images show wide angle red, blue and color composite views. The dark spots seen on three crater floors are probably small fields of dark sand dunes.