“Although prior research has sought to show planetary connections for the 819-day count, its four-part, color-directional scheme is too short to fit well with the synodic periods of visible planets,” the study authors write. “By increasing the calendar length to 20 periods of 819-days a pattern emerges in which the synodic periods of all the visible planets commensurate with station points in the larger 819-day calendar.” That means the Mayans took a 45-year view of planetary alignment and coded it into a calendar that has left modern scholars scratching their heads in wonder.
Mercury was always the starting point for the tricky timeline because its synodic period — 117 days — matches nicely into 819. From there, though, we need to start extrapolating out the 819 number, and if you chart 20 cycles of 819, you can fit every key planet into the mix. And Mars may be the kicker for the overall length. With a 780-day synodic period, 21 periods match exactly to 16,380, or 20 cycles of 819. Venus needs seven periods to match five 819-day counts, Saturn has 13 periods to fit with six 819-day counts, and Jupiter 39 periods to hit 19 819-counts. “Rather than limit their focus to any one planet,” the authors write, “the Maya astronomers who created the 819-day count envisioned it as a larger calendar system that could be used for predictions of all the visible planet’s synod periods, as well as commensuration points with their cycles in the Tzolk’in and Calendar Round.”