Transit of Phobos from Mars north of 70.4°N; for some days in the year, its shadow misses the surface entirely and falls north or south of Mars. At any given geographical location on the surface of Mars, there are two intervals in a Martian year when the shadow of Phobos or Deimos is passing through its latitude. During each such interval, about half a dozen transits of Phobos can be seen by observers at that geographical location (compared to zero or one transits of Deimos). Transits of Phobos happen during Martian autumn and winter in the respective hemisphere; close to the equator they happen around
Transit of Phobos from Mars Transit of Phobos from Mars A transit of Phobos across the Sun as seen from Mars takes place when Phobos passes directly between the Sun and a point on the surface of Mars, obscuring a large part of the Sun's disc for an observer on Mars. During a transit, Phobos can be seen from Mars as a large black disc rapidly moving across the face of the Sun. At the same time, the shadow (antumbra) of Phobos moves across the Martian surface. The event could also be regarded as a particularly quick and shallow annular solar eclipse by Phobos. A