 Unlike Phobos, which orbits so fast that it rises in the west and sets in the east, Deimos rises in the east and sets in the west.The Sun-synodic orbital period of Deimos of about 30.4 hours exceeds the Martian solar day ("sol") of about 24.7 hours by such a small amount that 2.48 days (2.41 sols) elapse between its rising and setting for an equatorial observer.From Deimos-rise to Deimos-rise (or setting to setting), 5.466 days (5.320 sols) elapse.