"Phobal" eclypse (1) - Sol 639

NASA's MER Spirit continues to take advantage of favorable solar power conditions to conduct occasional nighttime astronomical observations from the Summit Region of Husband Hill. Spirit has been observing the martian moons Phobos and Deimos to learn more about their orbits and surface properties. This has included observing eclipses. On Earth, a solar eclipse occurs when the Moon's orbit takes it exactly between the Sun and Earth, casting parts of Earth into shadow. A lunar eclipse occurs when the Earth is exactly between the Sun and the Moon, casting the Moon into shadow and often giving it a ghostly orange-reddish color. This color is created by sunlight reflected through Earth's atmosphere into the shadowed region. The primary difference between terrestrial and martian eclipses is that Mars' moons are too small to completely block the Sun from view during solar eclipses.
Recently, Spirit observed a "lunar" eclipse on Mars. Phobos, the larger of the two martian moons, was photographed while slipping into the shadow of Mars.