 As seen from Phobos, Mars would appear 6,400 times larger and 2,500 times brighter than the full Moon appears from Earth, taking up a quarter of the width of a celestial hemisphere.An observer situated on the Martian surface, in a position to observe Phobos, would see regular transits of Phobos across the Sun.Several of these transits have been photographed by the Mars Rover "Opportunity".