Which Babylonian tablet records observations of Venus over 21 years?

The Venus tablet of Ammisaduqa records observations of Venus over a 21-year period.

The tablet belongs to the Babylonian tradition of astronomical and astrological record keeping. It lists the appearances and disappearances of Venus, the planet associated with the goddess Ishtar, along with dates and omens. The observations are attributed to the reign of Ammisaduqa, a king of the First Dynasty of Babylon who ruled after Hammurabi.

The text survives in several copies and has attracted attention because astronomers and historians have used it in attempts to establish an absolute chronology for the ancient Near East. Some readings and interpretations remain debated because the tablet contains damaged passages and the observational records do not always align perfectly with modern expectations.

It should not be confused with MUL.APIN, a broader compendium of astronomical knowledge, or with Plimpton 322, a mathematical tablet containing numerical relationships associated with right triangles.