Taking advantage of extra solar energy collected during the day, NASA's
Mars Exloration Rover Spirit settled in for an evening of stargazing,
photographing the two moons of Mars as they crossed the night sky. Spirit
took this succession of images at 150-second intervals from a perch atop
"Husband Hill" in Gusev Crater on martian day, or sol, 594 (Sept. 4,
2005), as the faster-moving martian moon Phobos was passing Deimos in the
night sky. Phobos is the brighter object on the left and Deimos is the
dimmer object on the right. The bright star Aldebaran and some other stars
in the constellation Taurus are visible as star trails. Most of the other
streaks in the image are the result of cosmic rays lighting up random
groups of pixels in the camera.
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 c
omposite with its panoramic camera using the camera's broadband filter,
which was designed specifically for acquiring images under low-light
conditions.