The renewal of the Grand Cycle of Venus' patterns in the sky occurs only once every eight years and was of enormous significance to the ancient Maya. Results of this effort to document and photograph this rare event may provide new insight into the architectural philosophy behind astronomically oriented Maya structures.

UPDATE note: The latest southernmost Venus rise just occurred and my photos came out nicely. Here are a couple. Click them to view larger copies. Meanwhile, keep watching the page for a complete update coming very soon!

11 January 2005 Venus rise 16 January 2005 Venus rise

Now, back to the story...
Uxmal's Palace of the Governor

The ancient Maya were very likely the most sophisticated astronomers and mathematicians of their era. Much evidence of their accomplishments was destroyed during the Spanish Conquest of the 16th Century but, during the past three decades, contemporary scholars have made enormous strides in understanding this mysterious culture.

Evidence has recently been uncovered providing a far more intimate connection between the planet Venus and the Maya culture, as embodied in the Palace of the Governor, a richly adorned building in Uxmal, the capital of an ancient city-state in western Yucatán. The Palace of the Governor and several other major structures in Uxmal are characteristic of the Terminal Classic Period, believed to have been completed in the early Tenth Century, A. D.

Front view of the Palace of the Governor

Diagram of Uxmal Long understood to be closely connected with Venus, owing to the more than 350 Venus-related glyphs adorning its architecture, the Palace of the Governor was also built with its long-axis skewed nineteen degrees with respect to the primary orientation of other Uxmal structures. In 1975, measurements from the Palace's central doorway (Aveni and Hartung) indicated that a perpendicular to the building's axis might define a sightline running across the center of the double-headed jaguar throne in its courtyard to a pyramid-like structure on the southeastern horizon. This direction, Aveni and Hartung determined, closely approximated the southernmost rise location of the planet Venus, an event which takes place only once every eight years.

Excavated Chac masks To the Maya who assiduously observed and worshiped Venus as a primary deity, this eight-year periodicity was extremely significant. The planet's synodic period (the time between successive conjunctions with the sun) is 584 days, during which it sweeps out one of five characteristic paths through the sky as both a morning and evening object. At the end of five synodic cycles, the patterns begin again. This periodicity is referred to by contemporary astronomers as Venus' "Grand Cycle." But, interestingly, it also corresponds nearly precisely to eight 365-day years. To the calendar-conscious Maya--well aware of the Earth's 365-day annual cycle--this must have provided a compelling demonstration of Venus' divine connections. Specific evidence of the significance of this five-to-eight relationship is suggested by the Maya numeral eight (a line and three dots) carved into the supraorbital plates of Chac masks found at the northwestern and northeastern corners of the Palace (the southern corners have not yet been excavated).

Since 1990, I had been preparing to document and photograph the actual occurrence of Venus' southernmost rise. Working with the assistance of Maya scholars, Harvey Bricker (Tulane University), Jeff Kowalski (Northern Illinois University), and Susan Milbrath (Florida Museum of Natural History), I traveled to Uxmal in September of 1996 to make preliminary measurements to capture the event which my calculations determined would take place in January 1997.


David Rosenthal
E-mail: n6tst--then the "at" (Note: As a result of the unavoidable nuisance now posed by spammers and their automated Web page-scanning, e-mail address-collecting software, I can no longer use the conventional address format [humorously, that aforementioned e-mail address-collecting software will likely find my "" address example, harvest it, and try to send spam to it. Ha!]).

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