This sequence of 19 images was taken in visible-wavelength light as the Thermal Emission Imaging System (THEMIS) camera on NASA's Mars Odyssey orbiter scanned across the Martian moon Phobos. THEMIS also recorded thermal-infrared imagery during the same scan. The apparent motion is due to progression of the camera's pointing during the 18-second span of the Sept. 29, 2017, observation, not from motion of Phobos. Timing is sped up by a factor of two in this animation. This was the first observation of Phobos by Mars Odyssey.