Eclipses at Mars

Deimos transiting the Sun (left); Phobos eclipsing the Sun (center), lunar eclipse at Phobos (right). click for larger pictures. pictures courtesy NASA/JPL/Cornell (left, center) and NASA/JPL-Caltech/Cornell (right)

The Twin Rovers mission observed Sun and lunar eclipses as seen from Mars. Both moons of Mars, Phobos and Deimos are mere rocks, likely asteroids captured by Mars. Phobos is about 17-mile wide (27 km) and Deimos 9-mile (15 km). At night, a full Phobos shines at the -10 magnitude (that means as intense than a quarter-Moon) as Deimos reaches the -6 magnitude only, that is a very bright star or a planet. Both moons are orbiting in the equatorial plane of Mars. Phobos is orbiting Mars in 7h ½ only, that is very fast. So fast, that it's rising West and setting East. And it's orbiting close to Mars. Deimos, at the contrary, works like most solar system moons, rising East and setting West (Deimos takes 30 hours to complete its orbit)

Mars, Phobos and Deimos at scale (sizes and distances). illustration site 'Amateur Astronomy'

A seen from Mars, the Sun has a 10-arcminute apparent diameter as Phobos a 5-arcminute. These conditions mostly yield partial eclipses at Mars, as Deimos' small apparent diameter and large distance makes it appear a mere speck in front of Sun disk (Phobos covers a half of the Sun). As both moons are orbiting in the equatorial plane of Mars, such events occur frequently. Phobos is passing in front of the Sun about 1,300 times a years with each eclipse lasting 19 seconds. Deimos transits last 50-60 seconds. Phobos is projecting a 37 x 12 mi (60 km x 20 km) shadow. Viking landers in the 1970s observed the eclipse shadow moving on the landscape
Mars moon also endure moon eclipses. Mars Pathfinder e.g. saw Phobos emerging from Mars shadow in 1997 as Spirit, lately, took pictures of a lunar eclipse at Phobos (it lasted 26 minutes). The ensuing Curiosity mission also measured a drop in Sun's ultraviolet radiation during eclipses

Phobos orbits so close to Mars that gravitational tidal forces are dragging it down. In 100 million years or so, Phobos might well be disintegrating, the debris forming a decaying ring around Mars