Taking advantage of extra solar energy collected during the day, NASA's
Mars Exploration Rover Spirit settled in for an evening of stargazing,
photographing the two moons of Mars as they crossed the night sky. "It is
incredibly cool to be running an observatory on another planet," said
planetary scientist Jim Bell of Cornell University, Ithaca, N.Y., lead
scientist for the panoramic cameras on Spirit and Opportunity. This
time-lapse composite, acquired the evening of Spirit's martian sol 585
(Aug. 26, 2005) from a perch atop "Husband Hill" in Gusev Crater, shows
Phobos, the brighter moon, on the right, and Deimos, the dimmer moon, on
the left. Tiny streaks mark the trails of background stars moving across
the sky or the impact of cosmic rays lighting up random groups of pixels
in the image.
Scientists will use images of the two moons to better map their orbital
positions, learn more about their composition, and monitor the presence
of nighttime clouds or haze. Spirit took the five images that make up this
composite using the panoramic camera's broadband filter, which was
designed specifically for acquiring images under low-light conditions.