Ancient cultures, especially the Sumerians, already possessed great knowledge in astronomy, astrology, mathematics and geometry some 5000 years ago. It is also well known that they observed and recorded the synodic cycles of the Moon, Venus and some of the other planets. They were able to predict the occurrence of eclipses for centuries ahead. However, this required awareness about the so-called Saros cycle – a knowledge that originated with the Sumerians. John N. Harris, an expert on Babylonian astronomy, is convinced that the Babylonians and Sumerians not only observed and understood celestial mechanical phenomena, but clearly knew how to compute the various synodic periods.
The Maya, for example, had a Venus calendar and were able to calculate the phases of Venus, as well as its transits. But in order to accomplish that, they had to know by how the much the node line of Venus moves over a certain time period.
Nobody denies that the long term accuracy of the Mayan Calendar is about three times better than that of the modern Gregorian calendar. In order to calculate the leap years, the Mayans knew how to integrate the numbers 13 and 20 into their calendar system. Supposedly they also had a calendar of 260 days (13 x 20). What purpose did that serve?
For the observer (astronomer) on Earth there are only 3 important crossings or nodes for orientation purposes: the equinoxes to determine the tropical year, the Saros cycle for the lunar calendar and for calculating solar and lunar eclipses, and the Venus node line to determine the phases and transits of Venus. It seems that a 260 day-calendar makes little sense, because without a proper reference point it leads into total chaos.
Just as we have the Decimal and the Binary system, the Maya had a numeral system based on the number 20. This leads us back 4862 years (20 × 243 + 8 - 6) to the possible beginning of the calendar of the Maya, or rather the one of their ancestors.
During that period the node line of Venus was approx. 44.47° distant from the Galactic Center, and the upper transit of Venus occurred on the 22nd of April.
John Major Jenkins, Maya expert and author of "Galactic Alignment", offers evidence that in the year 2012 the Maya calendar reaches its end or climax. Apparently in that year the winter & summer solstice will be aligned with the Galactic Center.
And since the next Venus transit will be on June 6, 2012, twenty 251-year Venus cycles occurred since 2856 BC. Except for these two events - the alignment with the galactic center and the Venus transit, which depends upon the synchronous node line movement – there is no other significant celestial phenomenon occurring in the year 2012.
The fact is, as we shall see later, that the synodic motion is 32.88" annually. The movement of the Venus node line is in the opposite direction and according to NASA data the rate happens to be 32.44” per year. This implies that an isolated or central transit occurred about 9000 years* ago. And based on the same data, regular transit pairs occurred again for the first time roughly 7600 years later, after May 22, 554 AD.
*(32.88" minus 32.44" = 0.44"; 32.88 ÷" 0.44" ÷ 2 × 243 years = 9079 years)
How ironic: The Maya and their predecessors could not have known anything about transit pairs, and thus they could at best have been aware about a 243-year cycle (2004). Yet they were able to predict the transit of the June 6th 2012, the end of the 20 × 251 cycle. As they lived before Hipparchus they did not know anything about the Precession of the Equinox, or did they? Evidently, they realized that the node line of Venus migrates in sync with the synodic cycle, which implies that transits always occur in pairs based on tropical time.