Results of Archaeoastronomical Observations at Izapa, December 2006

John Major Jenkins
Copyright. January 2007.

The purpose of this trip to Izapa (my fourth) was to confirm my earlier assessment of the Brigham Young University maps of the site that indicate the ballcourt aligns with the azimuth of the December solstice sunrise. Some questioning of this arose in my conversations with various scholars in 2000-2001, due to the 7 degree magnetic deviation that must be included in an accurate assessment of the maps. I had assessed this correctly when I researched Izapa in the mid-1990s for my book Maya Cosmogenesis 2012 (1998). However, one scholar questioned this, and I surmised that he had neglected to note the 7 degree deviation that must be added to the solstice azimuth calculation. Since neither the Brigham Young University scholars (including V. Garth Norman in his astronomical thesis on Izapa) nor any other writer I know of have ever provided a specific statement about the ballcourt's orientation, my own deductive reading of the maps has done little to convince my critics that the ballcourt is indeed aligned to the solstice — despite the maps in the definitive BYU publications on Izapa that I can point to. So, documentation at the site seemed called for. The end result is confirmation that the ballcourt at Izapa is aligned to the December solstice sunrise. A brief summary of the field research follows in three parts.

I. The solstice sunrise observation, December 28, 2006

II. Using the azimuth gnomon to measure the azimuth of the solstice sunrise at Izapa

III. Implications for interpreting the carved monuments of the Izapa ballcourt.

The author in front of Izapa Stela 11, Group B. December 29, 2006 (above)


The author with the azimuth gnomon in the Izapan ballcourt (above)

I. The solstice sunrise observation, December 28, 2006

I arrived in Tapachula on the evening of December 27 and got a room at Hotel Fenix. The next morning at 5:00 a.m., I took a taxi to the site of Izapa, about 10 km from town. I was prepared to step around the gate before the sun rose, but luckily the site's keeper, Francisco, arrived and let me in. He had me sign the book and didn't seem to care that I was there before the site was officially open. By now it was about 6:30 and the sky was brightening. I went to the ballcourt and waited. The view of the solstice sunrise horizon was somewhat obscured by trees in the distance. The sun, however, was visible through the trees just a few minutes after the time of sunrise, and I triangulated from different vantage points. Over the next hour I watched the sun rise and arc toward the south, providing a visually compelling alignment down the lengthwise axis of the ballcourt. It's undeniable — it's a solstice alignment.

Note that the sun's position is actually slightly right of the center axis of the ballcourt, although the off-center position of the stela on the far end gives the impression that the sun is slightly left of center. The visual confirmation of the alignment is adequately documented in these pictures. However, we must make a slight adjustment because the observation was made 7 days after the solstice. This adjustment amounts to a very small 12 minutes of arc, or 1/5th of a degree. In effect, the sun in the picture above needs to to be adjusted 1/5th of a degree to the right (or south) in order to arrive at the position of the sun on the solstice. If this was done in the photo above, the difference would be barely noticeable, as the relative sizes and the actual distance of shift demonstrates in the following diagram:

The sun circle on the right shows the adjusted position. One can see that the effect is negligable. It still places the sun in an equally accurate position as a visually compelling alignment. From an off center angle we can see the striking effect of the dawning sun illuminating the ballcourt:

Thirty minutes after sunrise (above)

Sun illuminating the throne on the west end of the ballcourt (above). And just a few minutes later:

View of solstice sunrise illuminating the throne on the west end of the ballcourt (above).

II. Using the azimuth gnomon to measure the azimuth of the solstice sunrise at Izapa

I wanted to have a secondary confirmation of my observation of the solstice sunrise at Izapa. So I designed a little astronomical instrument I call the azimuth gnomon. This instrument requires taking a measurement at precise solar noon. I had a GPS watch with me, and I calibrated it to Greenwich Universal Time via satellite connection an hour before taking the measurement. The precise time of solar noon at Izapa, on December 29, was 12:11:28. At this moment the shadow must be lined up to the 0 degree azimuth mark on the azimuth gnomon, as shown:

Then the sunrise azimuth can be sighted with the two vertical target rods that are separated by a pre-measured 115 degree angle — the azimuth of the December solstice sunrise at Izapa, adjusted for horizon elevation (according to V. Garth Norman, 1980):

The aligned vertical rods target the sunrise azimuth position at the horizon (0 degrees altitude). As the sun rises it will angle upward and to the right, providing a perfect visually compelling alignment by the time it clears the trees. Note, again, that the rightward offset of the stela gives the impression the alignment isn't "on target" but in fact the alignment is right down the center of the ballcourt. We can analyze the visual frame more precisely by adding a grid:

The vertical red line shows the mid-line of the ballcourt. The precise sunrise azimuth is very slightly north (left) of this line, which is to be expected, since even the treeless horizon contains a slight elevation of distant hills (see diagram in my book Maya Cosmogenesis 2012). The sun in the photo has angled slightly to the south after rising.

One other consideration — changes in the obliquity of the ecliptic between 100 BC and today. This will slightly change the rise azimuth of the solstice sun. Today, the obliquity of the ecliptic is 23 degrees 27 minutes. As solstice alignments at Stonehenge, Newgrange, and elsewhere show, this variable does not effect the solstice rise position of the sun very much.

Conclusions. My visual observation and my azimuth gnomon instrument confirm that the ballcourt is aligned to the December solstice sunrise today, and thus by extension was also aligned to the solstice sunrise horizon 2,100 years ago. It should also be noted that, apart from the quest for absolute scientific precision in measuring these things, the visually compelling alignment is obvious to the naked eye and could even allow for a larger imprecision than actually exists.

III. Implications for interpreting the carved monuments of the Izapa ballcourt

At the very least, all investigators should now be able to agree that a solstice alignment exists in the Izapan ballcourt. I believed this to be true twelve years ago, based on a correct assessment of the BYU maps, and my analysis of the carved monuments in the ballcourt utilized this fact as an interpretive aid. Izapan astronomy and iconography go together, as is clear from other Izapan monuments such as Stela 25, where the imagery on the monument encodes the astronomy happening over its associated horizon. In the case of Stela 25, several astronomical features are involved: the Big Dipper, the sun, and the Milky Way. In the case of the monuments in the Izapan ballcourt, I've suggested that they are united by the same astronomical theme, involving the December solstice sun, the Milky Way, and the dark rift in the Milky Way, with a secondary reference to the Big Dipper to the north. My ideas were published in my books The Center of Mayan Time (1995), Izapa Cosmos (1996), Maya Cosmogenesis 2012 (1998), and Galactic Alignment (2002), and in numerous articles through the years. A helpful web page for understanding the iconographic content of the other monuments in the ballcourt is here: Also see the indispensable associated page:

In summary, the carved monuments encode the astronomy happening over the December solstice sunrise horizon. Specifically, they encode iconographic statements about the astronomical alignment of the December solstice sun with the dark rift in the Milky Way. This is a rare alignment within the cycle of the precession of the equinoxes, and occurs in the years around the Maya Long Count calendar end date: December 21, 2012. My thesis has been that Izapa is an important place to understand "the very important adoption of the Long Count calendar," as Mayanist Michael Coe said. And, I would add, the cosmology and beliefs associated with it. Izapa's ballcourt preserves evidence for nothing less than a profound galactic cosmovision developed by the early Maya at least 2,100 years ago — an awareness of a rare galactic alignment that occurs only once every 26,000 years and culminates in our current era. It is my hope that this confirmation can move the discussion about 2012 forward, and that Maya scholars can begin to honestly and seriously consider my thesis that the 13-Baktun cycle ending of 2012 was intentionally placed to target the rare alignment of the December solstice sun with the Milky Way's dark-rift and the co-spatial Milky Way / ecliptic crossroads.

The author at Yaxchilan. Photos by Brad and Lion Fire.

John with Liz and Will at Yaxchilan, January 2, 2007


January 17, 2007. John Major Jenkins.