This implies that the Mayan must have been recording the positions of the planets with great accuracy over a rather long period of time, probably spanning several generations.
* The current date in the 365-day solar calendar (18 months of 20 days + 5 extracalendrical days)
* The current date in the 260-day ritual calendar (13 "months" of 20 days, the months don't work like regular months we're used to)
* The "long count" date, i.e., the number of days elapsed from August 11, 3114 BC in proleptic Gregorian
* A 9 day cycle (roughly equivalent to our weekday)
* The date of the current lunar month
* The length of the current lunar month (29 or 30 days)
* A counter to keep track of where the lunar month is in terms of 29 or 30 day months
* The 819-day cycle, discussed in this article.
That is a sheer amount of information to be repeated (dates were the first aspect of Maya script to be deciphered, simply because a very large fraction of the text on stelae at Mayan are just these dates), and probably one of the reasons for this complexity is a way of showing off astronomical prowess (there are actually a few different correlations to lunar months in use at the same time, depending on which major polity's tables you wanted to follow).
Of particular note is that the main long-distance counting is the Long Count, which is a literal count of days elapsed since creation. There's no evidence of regnal dating system, which is very unusual compared to Eurasian calendars where maintaining dates across different kings is more of an occasional pastime rather than common dating format. This counting of days makes it extremely easy to work out long-distance periodic relationships. Given that we already have hundreds of years of date keeping being recorded before the 819-day cycle appears (IIRC, it's a late innovation in Classic Maya), it's virtually certain that reliable records spanning centuries could have been collected by the Classic Maya.