Naming of moons to as "Proserpina". More recently, especially in science-fictional contexts, the Moon has been called by the Latin name "Luna", presumably on the analogy of the Latin names of the planets, or by association with the adjectival form "lunar". In technical terminology, the word-stems "seleno-" (from Greek "selēnē" "moon") and "cynthi-" (from "Cynthia", an epithet of the goddess Artemis) are sometimes used to refer to the Moon, as in "selenography, selenology," and "pericynthion." 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
Transit of Phobos from Mars the autumnal equinox and the vernal equinox, while farther from the equator they happen closer to the winter solstice. Observers at high latitudes (but less than 70.4°) will see a noticeably smaller angular diameter for Phobos because they are considerably farther away from it than observers at Mars's equator. As a result, transits of Phobos for such observers will cover less of the Sun's disk. Because it orbits so close to Mars, Phobos cannot be seen north of 70.4°N or south of 70.4°S; observers at such latitudes will obviously not see transits, either. Mars Rover "Opportunity" rover photographed transits of