Astronomy
In comparison to the ancient peoples
of the Old World (Egyptians, Mesopotamians, Chinese, Greek), the methods used
by the Maya for astronomy were rudimentary. The Maya used a pole set upright on
the ground to mark the moment when the sun passed by the zenith of a particular
spot and rods with intercrossed threads to trace the sight lines to significant
astronomical points. We know some buildings were constructed for astronomical
purposes, amongst these, the so called Caracol or Observatory at Chichén Itzá
and Mayapán, the tower of the Palace at Palenque and the F. Group Complex at
Uaxactun. In these structures sight lines leaving from a point on the staircase
of the pyramid and directed towards three temples aligned on a platform
opposite, determine the points on the horizon from where the sun rises at the equinoxes
and solstices.
Despite the lack of accurate
instruments the Maya determined precisely the cycles of the moon, the sun and
of Venus, as well as some of the constellations. For the Moon they observed a
cycle of approximately 29 and a half days. According to the Dresden Codex their
exact calculation was for 29.53086 days and today modern scientists calculate
the figure as 29.53059 days.
According to modern observations
the actual tropical year (the solar cycle) has a duration of 365.2422 days.
With the addition of the leap year every four years in the Gregorian calendar,
the cycle is estimated at 365.2425 days, which is more accurate than the
Gregorian calendar by one day in every 10 thousand years. The correction to the
accumulated error was made with the civil calendar of 365 days.
For the cycle of Venus they
established a pattern of 584 days divided into different phases. The morning
star phrase was 236 days, for 90 days the planet disappeared, returned for 250
days in the evening star phase and then finally another disappearance, this
time for 8 days. In modern astronomy, the Venus cycle has the following phases,
respectively: 240, 90, 240, 14 with a total duration oscillating between 580
and 587 days, averaging 583.92 days.
Although it is unproven, the Maay
ought to have known the cycles of the other planets whose hieroglyphs appear on
their inscriptions. Great importance was given to stars and constellations.
Some of the most important ones were the Pole Star Xaman Ek, or the big
star, that guided merchants and travelers, the Pleiades or Tzab, “the
rattles” and Geminin or Ac, “the turtle”. The representation of animals
hanging from the celestial belt in the Paris Codes has led to the suggestion
that a zodiac was used for some prophesying.
In the Dresden Codex, a table or
register predicting eclipses has been identified that is valid for 33
consecutive years, and repeated to infinity. Modern calculations show that the
table is in general accurate. Differences are small, not exceeding one day. (Alberto
Rus Lhuillier, The Ancient Maya [trans. Margaret Shrimpton; Mérida, Mexico: Dante, 1992], 37, 39)
