Dust gradually obscures the Sun during a blue-sky martian sunset seen in a sequence of newly processed frames from NASA’s Mars Exploration Rover Opportunity. “It’s inspirational and beautiful, but there’s good science in there, too,” said Dr. Jim Bell of Cornell University, Ithaca, N.Y., lead scientist for the panoramic cameras on Opportunity and its twin, Spirit. The amount of dust indicated by Opportunity’s observations of the Sun is about twice as much as NASA’s Mars Pathfinder lander saw in 1997 from another site on Mars.