“Astronomy in Mexico before and after the Conquest”

We present to the readers of Chronicle the booklet that won the prize Antonio Garcia Cubas 2022coordinated by astronomers Susana Lizano Y Luis Felipe Rodriguez Jorge. Three of the most outstanding specialists in archaeoastronomy and history of astronomy participate in it, who analyze astronomy in Mesoamerica and Europe before and after the Conquest.



To our first intelligent ancestors, some two million years ago, nature must have seemed impossible to understand and even more difficult to predict. Game herds might be large one year and few the next. Floods, earthquakes, plagues, and other natural disasters occurred without rhyme or reason.

Yet in all this chaos there was hope. The Sun rose and set each day, and the periodic appearance of the full Moon was used to mark the passage of time. Unlike planet Earth, the sky was predictable. This led Aristotle to divide the universe into two regions: the sublunary and the supralunary, below and above the Moon. The sublunary world was imperfect and changing while the supralunary was perfect and immutable.

[…] All the great cultures, both ancient and current, have considered astronomy an essential activity. In ancient times the motivations were practical, such as agricultural planning and navigation through the stars, but they were also religious. The rulers presented themselves as mediators between the gods of the supernatural world and human beings. For this reason, it was essential to know the calendar well in order to perform the sacred rituals at the precise moment, guaranteeing the continuity of the universe. The rulers had to be able to alert the people of phenomena such as lunar and solar eclipses.

[…] In this booklet we have wanted to compare the astronomy of the ancient Mexicans with the European astronomy before and after the Conquest. For this, we have invited three of the most outstanding specialists of our country in the topics of archaeoastronomy and history of astronomy: Jesús Galindo Trejo, Stanislaw Iwaniszewski and Marco Arturo Moreno Corral.

Jesús Galindo Trejo takes us on a journey, marvelously illustrated with photographs through the evidence left by the ancient Mexicans of their astronomical activity. Many of the pre-Hispanic buildings are aligned with the rising or setting of the stars on important days for the calendar. This reminds us that Moctezuma, the Mexica emperor, proposed demolishing the Templo Mayor because it was not well aligned to the desired orientations. This, more than a construction error, could be a consequence of the rearrangements of the lake area.

Luis Felipe Rodríguez is a pioneer of radio astronomy in Mexico.

The National College

[…] Stanislaw Iwaniszewski uses another line of research in pre-Hispanic astronomy: that provided by the codices and inscriptions on stelae. He focuses on the establishment of the lunar theory of the Maya, an area in which they achieved extraordinary knowledge. The Sun gives us warmth and life, while the Moon gives us inspiration and fantasy. The lunar month, the period between a phase of the moon and its repetition, is 29.53 days. Thus, if we want to predict when the full moon will repeat itself, we can start by keeping a calendar in which 29 and 30 days alternate. This will give us an average of 29.5 days, quite close to the true value. However, with the passage of enough “moons” we will be behind the return of the full Moon. To remedy this, the trick the Maya (and other ancient cultures) used was to substitute a 29-day month for a 30-day month. This strategic intercalation of 30-day months instead of 29 led the Maya to have extensive calendars. of 126 lunar months in a period of 4784 days, giving an average of 29.53 days.

[…] Finally, Marco Arturo Moreno Corral gives us an overview of astronomy in Mexico in the centuries after the Conquest. Although the astronomical knowledge of the ancient Mexicans and the Europeans was comparable, it must be recognized that the Europeans had put it to a more practical use. For the first time in written human history, those explorers moved away from all reference points on the coast and entered the vast ocean, aided by their knowledge of the celestial vault. […] Astronomy provided the conquerors with a reliable method of establishing the geographic coordinates of the lands they were invading.

Billboard of the National College.

Billboard of the National College.

[…] Currently, astronomy practiced in Mexico is one of the disciplines with the greatest international impact. Let us think that this is not an accident, but that it reflects the ancient and continuous tradition of this science in our country.

*Members of the National College

previous collaborations

The National College in “Chronicle”

Luis Fernando Lara*

Adolfo Martinez Palomo*

Luis Felipe Rodríguez Jorge *

“Astronomy in Mexico before and after the Conquest”