Spirit Phobos Eclipse Animation
NASA's Mars Exploration Rover Spirit observed the Martian moon Phobos
entering the shadow of Mars during the night of the rover's 675th sol
(Nov. 27, 2005). The panoramic camera captured 16 images, spaced 10
seconds apart, covering the period from when Phobos was in full sunlight
to when it was entirely in shadow. As with our own Moon during lunar
eclipses on Earth, even when in the planet's shadow, Phobos was not
entirely dark. The small amount of light still visible from Phobos is a
kind of "Mars-shine" -- sunlight reflected through Mars' atmosphere and
into the shadowed region.
This clip is a sequence of the 16 images showing the eclipse at about 10
times normal speed. It shows the movement of Phobos from left to right as
the moon enters the shadow. Scientists are using information about the
precise timing of Martian moon eclipses gained from observations such as
these to refine calculations about the orbital path of Phobos. The precise
position of Phobos will be important to any future spacecraft taking
detailed pictures of the moon or landing on its surface.