Most of the archaeoastronomical information from the Maya area concerning the movement of the Sun, Moon and planets like Venus, Mars and Mercury has been found in the Postclassic codices. In the recent issue of Science, Saturno, Stuart, Aveni and Rossi report on early 9th century wall paintings from the site of Xultun that includes numerical tables and a series of long numbers that appears to work in the same way as the astronomical tables found in the later codices.
Many bar-and-dot numbers are arranged in vertical columns. These contain no more than three numerals. On top of at least five columns there are “Moon” glyphs that are combined with the facial profiles of deities. Similar glyphs are used to record Moon ages in the Lunar Series. The authors argue that the numbers represent elapsed days as they were recorded in the Long Count (tun, winal and kin). The span between two columns is almost a lunar “semester” of 177 or 178 days (29,5 days x 6). These numbers are important in Maya archaeoastronomy since the eclipse tables in the Dresden Codex use the same intervals. They are not correlated to precise eclipse phenomena. It makes up a tally that spans a period of roughly 13 years (4784 days to be precise).
There is another array of four columns in red colors. Here each column begins with a tzolkin day station. Below them are five numbers but they are not Long Count dates but are believed to be Distance Numbers with a duration between 935 and 6703 years. The intervals of the columns do not link the different tzolkin day stations and this indicates that the each column is self-contained. These four intervals have one common divisor and that is 56,940 days which is a multiple of the Calendar Round (3 x 18980 days) and the canonic Mars period (73 x 780 days). The authors believe the wall paintings may have been copied from Late Classic codices. The significance of this discovery is that we now have the first evidence of Classic period astronomical tables similar to the ones in the 4-6 centuries later codices.
Saturno, William A., David Stuart, Anthony F. Aveni, and Franco Rossi (2012). Ancient Maya Astronomical Tables from Xultun, Guatemala. Science, Vol. 336, 714-717.