High in the Columbia hills and with power to burn, Spirit performed many astronomical observations during its second Martian summer, including capturing the six frames for this animation of Phobos and Deimos moving past each other in the sky in the wee hours of the morning on sol 590 (August 30, 2005). Phobos is the larger of the two, moving quickly from west to east, while Deimos is the slower-moving, smaller, and more distant one.

NASA / JPL / Cornell / animation by Emily Lakdawalla