Symbols of Planets and Zodiacal Constellations

Some planetarium softwares or even some printed data are using symbols to represent planets. Planets symbols are thought to originate in the Middle Ages, if not earlier. Recentest planets, that is Uranus, Neptune, and Pluto which were discovered in modern times, got their symbol at the time of their discovery or later. Planets' symbols are used too in astrology. The symbols of the twelve zodiacal constellations on the other hand, seems to originate no earlier than the late Middle Ages. They are found in Greek manuscripts of this era. They are now mostly used for astrological purposes

Symbols of the planets are figurative, that is they symbolize some aspect or attributes of the planet in question. Mercury is shown under the form of its winged helmet and caduceus. Venus is symbolised by a hand mirror. The Earth's symbol features the equator and a meridian. Mars is represented by the god of war's shield and spear. Jupiter is illustrated either by the hieroglyphic symbol of an eagle, the god's bird, the abbreviated "Zeus" initial letter, or the schematisation of a thunderbolt. Saturn's symbol is a sickle (also said "scythe"). The symbol itself is varying for Uranus. It's either the "H" of Herschell who discovered the planet or a combination of the symbol of Sun and the spear of Mars (as Uranus was the personification of heaven, and heaven was considered dominated by the light of the Sun and the power of Mars). The second symbol only is found on the picture above. The symbol for Neptune came more surely back to the Greek mythology, as Neptune's symbol is the god of sea's trident. At last, the symbol for Pluto innovated as it is a monogram made of the "P" and "L" found in Pluto (both letters may stand too for the initials of Percival Lowell, the astronomer who had initiated the planet's discovery). As far as the Moon and the Sun are concerned, they are represented by a crescent and a shield with a central circle respectively. The Moon may be further detailed by a first or a last quarter Moon to figure whether it's waxing or waning) as the central circle at Sun's symbol might be a the representation of a sunspot. picture NASA/Lunar and Planetary Institute

The symbols for the twelve constellations seem to be schematised figurations of the constellations and might originate into such figures as represented by the Egyptians. It is this people which pushed astrology in the form which is mostly still in use today. The list figured on the accompanying picture has to be considered temporary only as the accuracy of symbols may not be entirely guaranteed