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How is most knowledge of Hipparchus’s lost work preserved?

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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.

Most of the original writings of the Greek astronomer Hipparchus have not survived, leaving only one of his works in existence. Consequently, our knowledge of his lost scientific contributions relies primarily on second-hand reports and citations from later ancient authors.12

The most significant source for his astronomical work is the Almagest, a comprehensive compendium written by the astronomer Ptolemy in the 2nd century CE. Historians often look to Ptolemy’s own star catalog as a likely derivation of Hipparchus’s lost catalog, adjusted for precessional motion.12

Other ancient writers also provide critical, though often fragmentary, evidence of his work:
* The geographer Strabo preserved quotes from Hipparchus’s writings on geography.2
* Pliny the Elder documented Hipparchus’s creation of a star catalog.2
* Later astrological texts occasionally cite him as an authority on the correspondences between constellations and geographical regions.2