Deuteronomy 4:15,16,19
"The 819 day calendar is a combination of two other calendars: the
tzolk’in calendar, which is a 260 day cycle based on the movement of the
moon, and the haab calendar, which is a 365 day solar cycle.
The
tzolk’in calendar is used for divination and religious purposes,
while the haab calendar is used for agriculture and civil purposes.
while the haab calendar is used for agriculture and civil purposes.
One of the unique features of the 819 day calendar is its connection to
Venus, which was a significant celestial body for the Maya.
Venus
appears as both the morning star and the evening star, and its 
cycles
were closely observed and recorded by the Maya astronomers. The Maya
believed that Venus had a direct influence on human affairs and used it
to predict important events such as wars and the rise and fall of
rulers.
The Venus cycle lasts approximately 584 days, and it was believed that
every 104 Venus cycles (approximately 60,100 days), Venus would return
to the same position in the sky. This was known as the “Great Venus
Round” and was considered a very significant event. The 819 day calendar
was used to track Venus and predict when the Great Venus Round would
occur.
Scholars long suspected the ancient Maya 819-day calendar followed
astronomical events, specifically how long it takes a planet to appear
in the same place in the night sky as seen from Earth, known as the
synodic periods of planets.
Another important aspect of the 819 day calendar is its connection to
the concept of “trecenas,” which are 13 day periods within the tzolk’in
calendar. The 819 day calendar is composed of 63 trecenas, which are
believed to represent different aspects of the natural world and the
gods who presided over them.
Each trecena has a specific symbol and is
associated with a different deity or energy.....the first trecena is represented by the crocodile and is associated with
the god of creation and the beginning of life. The fourth trecena is
represented by the jaguar and is associated with war and sacrifice. The
ninth trecena is represented by the snake and is 
associated with
transformation and healing.
The Maya believed that the trecenas had a
direct influence on the events of the world and used them for divination
and prediction.....They used this knowledge to create calendars that could be used for both
practical and spiritual purposes. Like sacrificing virgins, Spanish
sailors and children.. And eating them.
But according to the new study, the cycles in the calendar cover a 
much larger timeframe than scholars previously thought.
“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 the visible planets,” said
Tulane University alumnus John Linden and Professor Victoria Bricker.
“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.”
Previously, scholars thought the calendar referred to four cycles of
819, but that time span didn’t sync neatly with the synodic periods of
all the planets that can be seen with the naked eye: Mercury, Venus,
Mars, Jupiter, and Saturn.
Linden and Professor Bricker discovered it takes 20 cycles of 819
days, which is about 45 years, to align with the synodic periods of all
visible planets.
Within 20 cycles, each planet goes through some number of synodic
periods a whole number of times: Mercury every cycle, Venus every 5
cycles, Saturn every 6 cycles, Jupiter every 19 cycles, and Mars every
20 cycles.
Each synodic period is less than 819 days, but only Mercury has one that happens a whole number of times within a single cycle.
“Rather than limit their focus to any one planet, 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 synodic periods,” the scientists said.”
JamesMarinero@Futurism/SciNews