Phaenomena

work by Eudoxus of Cnidus

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 16, 2026

Quick Summary

Phaenomena was a work by the ancient Greek mathematician and astronomer Eudoxus of Cnidus. It described constellations, the visibility of stars, and associated weather patterns. This work, along with Eudoxus's Mirror, significantly contributed to the development of observational astronomy in the Greek world.1

The Phaenomena was later versified by the poet Aratus and became influential, with commentaries by figures like Hipparchus. Eudoxus is also credited with establishing the first sophisticated geometrical model of celestial motion, which influenced astronomical thought for centuries.21

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

Eudoxus of Cnidus
Astronomer
In two works, Phaenomena and Mirror, Eudoxus described constellations schematically, the phases of fixed stars (the dates when they are visible), and the weather associated with different phases. Through a poem of Aratus (c. 315–245 bce) and the commentary on the poem by the astronomer Hipparchus (c. 100…
Read More
In two works, Phaenomena and Mirror, Eudoxus described constellations schematically, the phases of fixed stars (the dates when they are visible), and the weather associated with different phases. Through a poem of Aratus (c. 315–245 bce) and the commentary on the poem by the astronomer Hipparchus (c. 100…
Read More