Artemis) are sometimes used to refer to the Moon, as in selenography, selenology, and pericynthion. Mars The moons of Mars (Phobos and Deimos) were named by Asaph Hall in 1878, soon after he discovered them. They are named after the sons of the god Ares (the Greek equivalent of the Roman god Mars). Jupiter The Galilean moons of Jupiter (Io, Europa, Ganymede and Callisto) were named by Simon Marius soon after their discovery in 1610. However, by the late 19th century these names had fallen out of favor, and for a long time it was most common to refer to them in the astronomical literature simply as "Jupiter I", "Jupiter II", etc., or as "the first satellite of Jupiter", "Jupiter's second satellite", etc. By the first decade of the 20th century, the names Io, Europa, Ganymede, and Callisto had once again recovered popularity, but the later-discovered moons, numbered, usually in Roman numerals V (5) through XII (12), remained unnamed. By a popular though unofficial convention, Jupiter V, discovered in 1892, was given the name Amalthea, first used by the French astronomer Camille Flammarion. The other irregular satellites (discovered 1904 to 1951) were, in the overwhelming majority of astronomical literature, simply left nameless. No names were proposed until Brian G. Marsden suggested a nomenclature for these satellites in 1955. Although the 1955 names met with immediate acceptance in some quarters (e.g. in science fiction and popular science articles), they were still rarely if ever met in astronomical literature until the 1970s. Two other proposals for naming the satellites were made between 1955 and 1975, both by Soviet astronomers, E. I. Nesterovich (in 1962) and Yu. A. Karpenko (in 1973). These met no particularly enthusiastic reception. In 1975, following Charles Kowal's discovery of the satellite Jupiter XIII in 1974, the IAU Task Group for Outer Solar System Nomenclature granted names to satellites V-XIII, and provided for a formal naming process for future satellites to be discovered. Under the new process, Jupiter V continued as Amalthea, Jupiter XIII was named Leda in accordance with a suggestion of Kowal's, and all previous proposals for the seven satellites VI-XII were abandoned in favor of new names, in accordance with a scheme suggested by the German philologist Jürgen Blunck where prograde moons received names ending in 'a' and retrograde moons received names ending in 'e'. The new names met considerable protest from some quarters. Kowal, despite