A peer-reviewed study in Science Advances revisited the Eclipse Table of the Dresden Codex and found that the Maya used it as a paper calculator for solar eclipses rather than as a symbolic list of dates.
The Dresden Codex, a 12th-century manuscript of 39 bark-paper sheets that unfolded to about 3.56 meters, contained an eight-page section spanning 405 lunar months - 11,960 days - equivalent to 46 cycles of the 260-day Maya ritual calendar. The authors wrote that this link let astronomers know on which ritual days each solar eclipse would fall, blending observation with spirituality.
Across the 405 lunar months, the table listed 69 new-moon dates, dedicating 55 to eclipse prediction and inserting 14 artificial dates to keep the arithmetic consistent. “The eclipse table evolved from a more general table of successive lunar months: the Maya diviners discovered that 405 new moons almost always equaled exactly 46 of these 260-day cycles,” said John Justeson, professor of anthropology at the State University of New York at Albany, according to Phys.org.
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To keep predictions accurate for more than seven centuries, the Maya used overlapping tables and periodic readjustments. Instead of restarting calculations at the end of a cycle, they reset the next table 223 or 358 months before the previous one ended, a step that corrected for cumulative errors. By combining four readjustments of 358 months with each one of 223 months, day keepers accounted for every observable eclipse in their region between 350 and 1150 CE. Modeling against a historical database of eclipses confirmed the system’s consistency.
The Saros cycle of 223 synodic months and the Inex cycle of 358 synodic months were embedded in the schema. The team reconstructed how priests and scribes wove periods of five and six lunar months - intervals when the moon returned to the same alignment with Earth and the sun - into windows when eclipses were most likely. “The 405-month eclipse table had emerged from a lunar calendar in which the 260-day divinatory calendar commensurated the lunar cycle,” the authors wrote.
The study settled a long debate over whether the Eclipse Table was chiefly ritualistic or scientific. “Its creators were seeking a system that works over the long term, not just recording events after they occurred,” said Justeson in comments to Al Jazeera Net. He added, “About 1500 years ago, the Maya built a paper calculator for eclipses, a tool that predicts moments of the sun’s disappearance with remarkable accuracy, to serve religious, agricultural, and organizational affairs in their society.”
The table’s design went through stages of refinement. Priests and scribes practiced astronomical modeling based on lunar cycles and alignments, updating calculations across generations. The study said the Maya achieved this precision without Babylonian mathematics or telescopes; observation and calculation sufficed.
Solar eclipses held cosmic meaning for the Maya, who saw them as moments of divine anger or renewal. By coordinating the 260-day ritual calendar with precise lunar observations, Maya scientists turned observation into prediction. Modeling showed that the table would still forecast modern solar eclipses over Mexico today.