Canyon Observation Seasons & Alignments Time References Webcast
   

Fajada Butte

Tour the alignments:

Fajada Butte
Wijiji
Piedra del Sol
Cardinal Directions
Casa Rinconada
Pueblo Bonito

High atop the imposing butte at the entrance of the canyon is the most famous of Chaco’s sites. There, a set of spiral petroglyphs pecked into a cliff face behind three giant slabs of rock functions as a solar marker. At summer solstice, a vertical shaft of light pierces the main spiral exactly at its center. On the winter solstice, two shafts of light perfectly bracket the same spiral. Light shafts strike the center of a smaller spiral nearby on the spring and fall equinoxes.

Launch Sun Dagger Demo
Explore the interactive Sun Dagger demonstration.

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This site, now known as the Sun Dagger, was discovered by Anna Sofaer in 1977. After extensive investigation, Sofaer and her colleagues published data that showed that the spirals may also track the 18.6-year lunar cycle.

Alas, it’s no longer possible to see the Sun Dagger in action. In 1989, the rock slabs shifted—possibly from increased erosion due to too many visitors—and the effect was spoiled. Today, the site is closed to visitors.


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