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How did Babylonian sexagesimal numbers influence Greek astronomy?

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Engraving of six astronomers, with Hipparchus seated at center and, from left to right, Galileo, Johannes Hevelius, Tycho Brahe, Nicolaus Copernicus, and Ptolemy standing, each holding scientific instruments. — Hipparchus “Six astronomers,” the frontispiece of *Astronomica Institutio* (1692) by Jan Luyts, engraving after drawing by Gerard Hoet. Hipparchus is seated at center with from left to right: Galileo, Johannes Hevelius, Tycho Brahe, Nicolaus Copernicus, and Ptolemy.

In the 2nd century BCE, the Greek astronomer Hipparchus played a pivotal role in restructuring Greek astronomy by integrating Mesopotamian observational data and computational methods with traditional Greek geometric models.12

While Hipparchus maintained a preference for the geometric approach of his predecessors, he adopted the Babylonian sexagesimal system for arithmetic computation. This system, which uses base-60, provided the Greeks with a powerful tool for the numerical measurement of angles and the construction of tables necessary for predictive astronomy.12

By incorporating these Babylonian parameters and computational techniques, Hipparchus and later astronomers were able to calculate the angular positions of planets more effectively. This synthesis of mathematical theory and observational data became a cornerstone of ancient astronomy, and the sexagesimal method remains in use today for measuring time and angles.21