Mars and Deimos. Computer artwork of how Mars (left) and its smaller moon Deimos (right) might appear from a distance of about 100 miles from the surface of Deimos. Beyond Mars, immediately to the left of its night side, is Phobos, another one of its moons, at a distance of 20,000 miles. The two bright objects in the lower left are the stars Beta Gruis and Al Nair in the southern constellation Grus.