Celestial Science & Mathematical Astronomy
From scanning the sky for omens grew real astronomy — the zodiac, eclipse prediction, the first exact science of the heavens.
Also: astronomy · Babylonian astronomy · MUL.APIN · zodiac · mathematical astronomy · celestial science · astronomical diaries · eclipse prediction
Out of centuries of watching the sky for omens, Babylonian scholars built one of the ancient world's great sciences. They catalogued the stars (the MUL.APIN compendium), divided the ecliptic into the twelve signs of the zodiac, tracked the planets, and devised arithmetical methods to predict lunar and planetary positions and eclipses with remarkable accuracy — without geometry, by pure calculation. This mathematical astronomy, the achievement of named late scholars and anonymous experts alike, was transmitted to the Greeks and underlies much of later astronomy and astrology. It is Mesopotamia's most enduring contribution to the exact sciences.
In short
The Mesopotamian observation and mathematical modeling of the heavens — star catalogues (MUL.APIN), the zodiac, and predictive planetary/lunar schemes — that grew out of celestial omen-watching into a true astronomy.
Where it’s found
MUL.APIN, the astronomical diaries, and the mathematical-astronomical texts (akkadian-pending; Hunger & Pingree, Astral Sciences in Mesopotamia)
How the idea developed across Sumer, Babylon & Assyria
A clear development: from celestial omens (Enūma Anu Enlil) to systematic observation (MUL.APIN, early 1st millennium) to predictive mathematical astronomy and the zodiac (mid–late 1st millennium, the 'astronomical diaries' and ephemerides). The zodiac as 12 equal signs is a Babylonian innovation (c. 5th century BCE).
The 12-sign zodiac is a Babylonian innovation of c. the 5th century BCE; present with that date.