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Babylonian astronomy

Nightly records kept for centuries reveal that the sky repeats.

When
Duration
250 years
Known to
± 50 years
Era
Iron Age, Holocene

Babylonian scribes maintain systematic observational diaries from around 750 BCE — positions of planets, eclipses, weather, river levels and commodity prices, night after night for over six centuries. The accumulated data lets them identify the Saros cycle of 223 months and predict lunar eclipses, and by the late period they compute planetary positions arithmetically. It is the longest continuous scientific observation programme in history, and Greek and later Islamic astronomy is built on it.

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