Researchers Fully Decode the Dresden Codex Eclipse Table

What happened

The Dresden Codex, one of only four surviving Maya books, devotes eight of its pages to an eclipse table whose full internal logic was reconstructed in a 2025 peer-reviewed study in Science Advances by John Justeson and Justin Lowry. Studying 145 solar eclipses visible in the Maya area between 350 and 1150 CE, the researchers concluded the table originally recorded a repeating cycle of 405 lunar months, each 29 or 30 days long, and was not initially built to predict eclipses at all. Maya astronomers later discovered that after 405 lunar months, equal to 46 cycles of the 260-day sacred calendar, the lunar and ritual calendars realigned, and that eclipses recurred on the same named day within that cycle, allowing them to repurpose the table for prediction. Justeson and Lowry propose the table's final version, anchored to a 32-year window beginning in either 1083 or 1116 CE, worked by resetting overlapping sub-tables at intervals of 223 or 358 months, both themselves eclipse cycles, correcting for the small errors that would otherwise accumulate over centuries of use.

How we know

The 2025 decoding is a peer-reviewed reconstruction (verified via Crossref against the published DOI) that tests the proposed 405-month and 223/358-month cycles directly against a modern astronomical catalog of 145 known historical solar eclipses in the Maya region, finding the model's predictions match.

Sources

• John Justeson, Justin Lowry, Science Advances. The design and reconstructible history of the Mayan eclipse table of the Dresden Codex · Peer-reviewed (author-declared)science.org · Cited as a "journal" source (no stronger domain match).
• Sky & Telescope. Maya 260-day Calendar Provides Key to Solar Eclipse Predictions · General sourceskyandtelescope.org · Cited as a "news" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)