Zodiac constellations can be traced even further back, to Bronze Age (First Babylonian dynasty) sources, including Gemini "The Twins", from MAŠ.TAB.BA.GAL.GAL "The Great Twins", and Cancer "The Crab", from AL.LUL "The Crayfish", among others. Around the end of the 5th century BC, Babylonian astronomers divided the ecliptic into twelve equal "signs", by analogy to twelve schematic months of thirty days each. Each sign contained thirty degrees of celestial longitude, thus creating the first known celestial coordinate system. Unlike modern astronomers, who place the beginning of the sign of Aries at the place of the Sun at the vernal equinox; Babylonian astronomers
Zodiac coordinate system, which measures astronomical positions by right ascension and declination rather than the ecliptic-based definitions of celestial longitude and celestial latitude. The word "zodiac" is also used in reference to the zodiacal cloud of dust grains that move among the planets, and the zodiacal light that originates from their scattering of sunlight. In Unicode, the symbols of zodiac signs are encoded in block "Miscellaneous Symbols": In Unicode 6.0 the sign for Ophiuchus has been added, too: Zodiac The zodiac is an area of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the