The Ptolemaic Zodiac Project – Recreating the cosmos as envisioned by Ptolemy

Background

Written in the 2nd century CE, Ptolemy’s Almagest was the most influential astronomical text for over 1,500 years. It contains the oldest known catalog of stars, giving the coordinates and brightnesses of 1,025 stars.

To identify which star was being described by a set of coordinates, Ptolemy would describe the figure of the constellation and how the star fit on it. Alternatively, he would describe the position of stars in relation to one another.

However, the way the figures of the constellations are imagined has changed in the nearly 2,000 years since Ptolemy. At the same time, there have been generations of corruptions of the coordinates. While historians have carefully reconstructed the catalog’s coordinates, an artistic reconstruction of the figures of the constellations based on accurate stellar positions has not been attempted. This project invites artisans from across the known world to imagine the cosmos as envisioned by Ptolemy.

A diagram of Capricorn from al-Sufi's Book of Fixed Stars (based on the Almagest) c964 CE. While it accurately depicts the stars in the figure as it was imagined at that time, the stars are not spaced as they would be on the sky.

A page of the star catalog from the Paris 2389 Almagest manuscript (7th - 9th century)

The Challenge

Participants are challenged to combine the descriptions from Ptolemy's star catalog with the stellar coordinates to produce an imagining of each of the 12 zodiac constellations that accurately represents the cosmos as described by Ptolemy.

The project officially begins March 20, 2023 with the first constellation (Aries) and will follow zodiacal the signs throughout the year until the zodiac is complete, repeating the cycle annually.

Details