For decades, the so-called Eclipse Table of the Dresden Codex has been one of the most persistent enigmas of Mayan astronomy. Although it was known since the early 20th century that its pages included predictions of solar eclipses, its mathematical foundations and the process of its creation remained a subject of debate. A recent study by John Justeson and Justin Lowry, published in 2025, finally provides a complete reconstruction of the model that underpinned this table. It demonstrates that the Mayan specialists responsible for calculating the calendars developed a predictive system based on centuries of observation and a sophisticated understanding of lunar cycles. The new analysis reveals that the table was the result of a long process of astronomical refinement that began around 350 CE and culminated between 1083 and 1116 CE. C.
An Exceptional System: The Foundations for Predicting Eclipses
Justeson and Lawry argue that eclipse prediction was only possible thanks to the profound familiarity that the Maya ajq’ij—the specialists responsible for keeping track of the calendar—had with the lunar cycle and the 260-day ritual calendar. At least since 500 BCE, the divinatory calendar had been associated with lunar phenomena, allowing the daily visibility of the moon to be linked to a position within the 260-day cycle. This correlation between lunar movement and the ritual calendar was essential for Maya astronomers to record patterns and anticipate eclipses with remarkable accuracy.
The key to predictability lies in the ability to recognize that eclipses can only occur when the moon passes through the nodes, the points where its orbit intersects the ecliptic. This happens approximately every 173 days. For the Maya, this periodicity was expressed as a succession of six-lunar intervals, although they sometimes had to insert eleven- or seventeen-lunar intervals to correct accumulated discrepancies. Based on these observations over time, specialists developed models capable of predicting solar eclipses visible from their territory.
The study demonstrates that the Dresden Codex Eclipse Table records 69 new moon dates distributed across 405 lunar cycles, equivalent to almost 32 years. Of these dates, 55 were designed to indicate the days on which a solar eclipse could be seen in the Maya region, while the other 14 were introduced as formal adjustments to maintain the pattern of six lunar cycles between successive seasons.
One of the crucial findings presented in the article suggests that the 405-lunar cycle was not originally conceived to predict eclipses, but rather as a much more general lunar calculation tool. This proved useful because 405 lunar cycles were roughly equivalent to 11,960 days, a figure close to a multiple of 260 days. This coincidence, therefore, allowed the lunar cycle to be linked to the ritual calendar, which, in turn, facilitated long-term correlations and, later, made the creation of eclipse tables possible.
One of the most innovative aspects of the study is the demonstration that the Dresden Codex table was the final result of a series of previous tables that were copied, corrected, and adjusted over several centuries. Thus, the analysis of copying errors, accumulated intervals, and internal patterns has allowed the reconstruction of 21 possible historical sequences, 16 of which would even predate the first epigraphic evidence of a Maya lunar calendar (361 CE).
The authors reject the old idea that each new table began on the last day recorded in the previous one. Instead, they identify two favorable points for restarting the cycle: months 358 and 223. This innovation, they argue, would have been essential for maintaining the system’s accuracy by allowing the tables to be updated without losing their predictive power for millennia.
The sophistication of the mechanism is demonstrated by the combined use of cycles of 358 and 223 lunar months, totaling 1655 lunar months. This interval would have been especially useful because it minimized anodal shift and kept eclipse predictions always in sync with astronomical reality.
On the other hand, the study also identifies four possible chronological intervals in which the table could have been compiled: 1043–1076, 1076–1108, 1083–1116, and 1116–1148. Each corresponds to a case in which an actual eclipse occurred on the same day of the ritual calendar as the beginning or end of the table. After comparing multiple variables (frequency of observable eclipses, nodal coherence, and internal symmetries), the study concludes that the most probable dates could be 1083–1116 or 1116–1148.
This hypothesis implies that the Dresden Codex table represents the culmination of astronomical knowledge accumulated over at least seven centuries. Its preservation in the manuscript is perhaps due to the fact that both its first and last stations coincided with actual eclipses visible in Maya territory. Such an exceptionally rare event would have justified its inclusion in the codex.
Justeson and Lowry’s study underscores that Maya calendars were scientific instruments in constant refinement. Over the centuries, Maya calendar experts verified hundreds of eclipses, both actual and predicted, and adjusted their models based solely on naked-eye observations. The accuracy achieved by the table can only be explained by this sustained effort, coupled with a profound understanding of celestial rhythms. The Eclipse Table of the Dresden Codex is, therefore, a testament to the Maya’s intellectual capacity to transform astronomical observations into far-reaching predictive models.
Source: muyinteresante.okdiario
