• celestial mechanics;
  • ephemerides;
  • history and philosophy of astronomy


The Maya used their own very precise calendar. When transforming data from the Mayan calendar to ours, or vice versa, a surprisingly large uncertainty is found. The relationship between the two calendars has been investigated by many researchers during the last century and about 50 different values of the transformation coefficient, known as the correlation, have been deduced. They can differ by centuries, potentially yielding an incredibly large error in the relation of Mayan history to the history of other civilizations. The most frequently used correlation is the GMT one (of Goodman-Martínez-Thompson), based largely on historical evidence from colonial times. Astronomy (celestial mechanics) may resolve the problem of the correlation, provided that historians have correctly decoded the records of various astronomical phenomena discovered, namely, in one extremely important and rare Mayan book, the Dresden Codex (DC). This describes (among other matters) observations of various astronomical phenomena (eclipses, conjunctions, maximum elongations, heliacal aspects, etc), made by the Maya. Modern celestial mechanics enables us to compute exactly when the phenomena occurred in the sky for the given place on the Earth, even though far back in time. Here we check (by a completely independent method), confirming the value of the correlation obtained by Böhm & Böhm (1996, 1999). In view of these tests, we advocate rejecting the GMT correlation and replacing it by the Böhm's correlation. We also comment on the criticism of GMT by some investigators. The replacement of GMT by another correlation seems, however, unacceptable to many Mayanists, as they would need to rewrite the whole history of Mesoamerica. The history of the Maya would be – for example with Böhm's correlation – closer to our time by 104 years. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)