PlanetQuest: The History of Astronomy
The Dresden Codex
Photograph © Andreas Fuls, Technische Universität
Today the eager scholar, whether child or academician, has at his or her fingertips
virtually all that humanity has learned of a subject. If he or she has access to the
internet, the information is literally at hand by way of the computer
keyboard! If not, the information can be found in books at any library or bookstore.
But human beings were exploring the Universe long before they could record their
discoveries in mass-produced collections of printed pages. Written records of
early scientific knowledge are rare and, to the historian at least, valuable
almost beyond compare.
The Dresden Codex is basically an astronomy textbook that was written between
1200 and 1250 AD in the part of the world known today as the Yucatán, in Mexico.
It is one of three codices (ancient manuscripts) that escaped destruction by
the Spanish conquistadors in the 16th century when they took over that region.
It turned up in Dresden, in what is now Germany, in the 1700s and has been there
ever since—hence the name.
The Dresden Codex is not the oldest astronomy textbook in existence. Not by
any means. Claudius Ptolemy's Almagest, containing an analysis of planetary
orbits, was written more than 1000 years before, and the Babylonians in the
19th century BC recorded astronomical information onto stone tablets. For that
matter, a bone with notches cut into it recording the lunar phases—not
exactly a "textbook," but believed by some to be the first written
record of astronomy—was carved 20–30,000 years ago, when the Earth
was still in the last Ice Age (see the article on the Blanchard
No, what makes the Dresden Codex so important is not so much its age, as the
fact that it is one of the only remaining written records of the remarkable
astronomical knowledge of the great Mayan civilization.
The ruins at Uxmal, including the Palace of the Governor (far left, in
which faces the southernmost rising point of Venus. Photograph © Clive Ruggles, University of Leicester
|Carvings on the Palace of the Governor at Uxmal, which include more
than 350 emblems of Venus.
Photograph © Clive Ruggles, University of Leicester
A careful look at Mayan cities shows that astronomy played a large part in
their culture. Numerous structures, such as the buildings and pyramids at Uxmal
or the famous Caracol of Chichén Itzá, have features that were
designed to line up with specific astronomical objects and events.
Apparently much of Mayan astronomical knowledge was used for purposes that
today would be called astrology—avoiding what they believed to be the
dangers associated with eclipses, or the disappearings and reappearings of Venus,
for instance. But this need not diminish our appreciation of the scope of their
accomplishment in learning so much about what goes on in the cosmos.
The Dresden Codex contains numerous astronomical tables and information in
its 74 accordion–style pages. For instance, one way in which the Mayans
measured time involved a sacred almanac of 260 days. One table in the codex,
a table that takes up eight pages in itself, covers a time span of 46 such almanacs,
counted out in groups of 177 and 178 days.
What is the explanation? Consider first of all that
solar eclipses were important to many ancient
civilizations since they were believed to signal dramatic, even terrifying events
in the heavens. Consider also that solar eclipses, which require perfect alignment
of the Sun, the Moon, and the Earth, can occur only once every six lunar cycles
(a lunar cycle is a complete cycle of lunar phases—from full Moon to full
Moon, for example). These are the so–called "eclipse seasons."
Finally, consider that six lunar cycles take 177 days, and it becomes clear
that this table in the codex is a chart for predicting solar eclipses.
Another table covers 65 of Venus's synodic revolutions (orbital cycles
as seen from Earth)—a time span of no less than 104 years. Unlike some
early cultures, the Mayans were aware that the "Morning Star" and
the "Evening Star" are one and the same; but they feared Venus’s
regular reappearance in the morning sky after its lengthy disappearance, and
so kept elaborate records to be able to predict its comings and goings.
These brief descriptions give only the merest glimpse of the complexities that
are found in the codex. Written in hieroglyphics on tree bark, using a logical
and easy-to-follow numerical system, it makes fascinating reading!
And it is an impressive accomplishment for a 13th century civilization.
Return to the Index
"The Dresden Codex," from the Technische Universität Dresden, available online
Hoskin, Michael, ed., The Cambridge Illustrated History of Astronomy, Cambridge
University Press, Cambridge, 1997.
Die Maya-Handschrift Codex Dresdensis (extensive information, mostly in German)
for the Advancement of Mesoamerican Studies, Inc. (FAMSI)
College History of Astronomy