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At summer solstice in 1977, Anna Sofaer, now president of the Solstice Project, was studying petroglyph art on top of Fajada Butte in Chaco Canyon in New Mexico. Near noon Sofaer witnessed a dagger shape of light cast by the opening of two large rock slabs bisect the center of a large large spiral carving on the rock wall behind the slabs. This site, subsequently called the Sun Dagger site, was created approximately a thousand years ago by the ancestral Puebloan culture of Chaco Canyon. In early 1978, Sofaer formed the non-profit Solstice Project to study and preserve this site, and to disseminate educational information about it and other astronomical works of cultures of the American Southwest.

Throughout the 1978 solar season, the Solstice Project's research team documented other light markings at the Sun Dagger site: at equinox a needle of light pierces a nearby smaller spiral and at winter solstice two parallel light daggers bracket the larger spiral.  In 1979, the Solstice Project's research revealed that the 18.6 year lunar standstill cycle was also marked by the moon’s shadow patterns on the large spiral. In 1980, the Solstice Project research team recorded numerous other light patterns on petroglyphs on Fajada Butte that mark repeatedly solar noon, the solstices and the equinoxes.

The Solstice Project has presented its research on the solar and lunar light markings on Fajada Butte in several scientific publications. It also produced "The Sun Dagger," an hour-length film narrated by Robert Redford. This film was broadcast nation-wide by PBS in 1982-1983. It received numerous awards, including the American Film Festival Blue Ribbon award.

In the 1980's and 1990's, the Project conducted extensive research on the constructions of the Chaco culture throughout the San Juan Basin. From investigations of the Chaco roads, the Project demonstrated that certain of these roads were probably symbolic expressions of the Chaco culture's cosmology. In particular, this study revealed that the Great North Road (coursing 35 north from Chaco Canyon) served no utilitarian purpose. This road appears rather to express the connection of the central architectural complex of the canyon with the direction north, a most sacred direction in the traditions of the Pueblo people.

With the assistance of the National Oceanic and Atmospheric Administration, the Project conducted a survey of the Chacoans' primary architecture. This survey revealed that twelve major Chaco buildings are oriented to the sun or the moon. In addition, the study showed that the internal geometries of the major buildings incorporate solar-lunar relationships. It also showed that the Chacoans organized their primary architecture in a complex regional pattern, with astronomical and religious implications. In this period, the Project also worked with NASA in developing a remote sensing study of the Chaco road network and with the Bureau of Land Management in further investigations of the roads.

In 2000, the Solstice Project produced a one-hour documentary entitled " The Mystery of Chaco Canyon," which demonstrates, in 3-D animation, the alignments of the Chacoan buildings to the sun and moon. Robert Redford also narrated this film and PBS debuted it in June 2000. It continues to be broadcast by local PBS stations. Both "The Mystery of Chaco Canyon" and the Project's earlier film "The Sun Dagger" have been distributed internationally and to schools and universities throughout the United States.

In 2006, the Project completed an archival model of the Sun Dagger site, with the assistance of laser scanners of Western Mapping, and of Alan Price, a professor and computer designer of Ohio State University. This model digitally restored with accuracy the astronomical functioning of the Sun Dagger site. It also serves as an open ended interactive model for research of the site's complex solar and lunar markings and its geometric relationships, providing tools for study of the site's original development. In 2009, Alan Price developed an educational version of this model for the Project that is now installed as The Sun Dagger Explorer at the New Mexico Museum of Natural History and Science.

In 2008, the Solstice Project's nine research papers were collected in a book entitled Chaco Astronomy: an Ancient American Cosmology published by Ocean Tree Books. The Project's documentation of the astronomical markings and alignments of the Chacoan culture have been presented in numerous museum exhibits and in several school and college textbooks. The Project continues to share its recent findings in talks and presentations to numerous scientific and educational groups.

The Project remains vigilant in the protection and archival preservation of the fragile remains of the Chaco civilization. Problems of erosion and vandalism and rapidly expanding energy development endanger this priceless heritage. The currently proposed paving of the main road into Chaco by San Juan County poses an imminent and severe threat to its protection.

Critical to the achievements of the Solstice Project has been its unique opportunity to draw upon the wide-ranging skills and creativity of an interdisciplinary team. Sharing a common fascination with the archaeoastronomy and cosmology of Chaco, these professionals, mostly volunteers, have ranged from archaeologists to mathematicians and astronomers; from remote sensing experts to filmmakers; from physicists to art historians and architects; from computer graphics experts to a Pueblo ethnographer and poets. The Project has been aided throughout its work by the thoughtful insights and sensitivities shared by Pueblo people. They have affirmed that Chaco is held in their traditions as a center of great historic and spiritual importance.

Support to the Solstice Project work has been provided by the Shaler Adams Foundation, the Joyce Foundation, the Educational Foundation of America, the Batir Foundation, the McCune Foundation and the Chamiza Foundation, and by individual donors.



The Solstice Project's research on the Sun Dagger site:
Sofaer, A., Zinser, V. & Sinclair, R.M. (1979), "A Unique Solar Marking Construct," Science, 206, pp 283-291; and Sofaer, A., Sinclair, R.M. & Doggett, L.E. (1982), "Lunar Markings on Fajada Butte, Chaco Canyon, New Mexico," Archaeoastronomy in the New World, ed. A.F. Aveni, pp 169-186, Cambridge University Press.

Sofaer, Sinclair and the Solstice Project research team's documentation of solar markings on Fajada Butte that record solar noon, the solstices and the equinoxes:
Sofaer, A. & Sinclair, R.M. (1986), "Astronomical Markings at Three Sites on Fajada Butte", Astronomy and Ceremony in Prehistoric Southwest, ed. J. Carlson & W.J. Judge, Maxwell Museum Technical Series, University of New Mexico.

Research demonstrating that the Chacoan roads were probably symbolic expressions of the culture's cosmology:
Sofaer, A., Marshall, M.P. & Sinclair, R.M. (1989), "The Great North Road: A Cosmographic Expression of the Chaco Culture of New Mexico", World Archaeoastronomy, ed. A. Aveni, Cambridge University Press.

The Solstice Project's survey of Chaco's primary architecture:
Sofaer, A., Sinclair, R.M., & Williams, R. (1987), "A Regional Pattern in the Architecture of the Chaco Culture of New Mexico and its Astronomical Implications", Bull. Am. Astronomical Society 19. No. 4, pp 1044; and Sofaer, A. (1997), "The Primary Architecture of the Chacoan Culture: A Cosmological Expression", Anasazi Architecture and American Design, University of New Mexico Press.
Sofaer, A., Sinclair, R.M., and Donahue, J. (1990), "Solar and Lunar Orientations of the Major Architecture of the Chaco Culture of New Mexico," Proceedings of the Colloquio Internazionale Archaeologia e Astronomia, University of Venice. In studying the internal angles of the Chaco buildings, the Project discovered a solar-lunar geometry; Sofaer, A., (1994), "Chacoan Architecture: A Solar-Lunar Geometry," Time and Astronomy at the Meeting of Two Worlds, University of Warsaw.  One key Chaco building, Pueblo Bonito, appears to be shown in its relationship to the sun in a petroglyph on Fajada Butte; Sofaer, A., (1994), "Pueblo Bonito Petroglyph on Fajada Butte: Solar Aspects," Celestial Seasonings: Connotations of Rock Art, Papers of the 1994 International Rock Art Congress, edited by E.C. Krupp.




At summer solstice in 1977 Anna Sofaer rediscovered the Sun Dagger site near the summit of Fajada Butte in Chaco Canyon New Mexico. Following this finding, Sofaer conducted three decades of research on her further astronomical findings. Through the non-profit Solstice Project, she has coordinated the work of interdisciplinary teams – including astronomers, archaeologists, anthropologists, architects, computer animators and remote sensing experts. Sofaer published much of this research in nine scientific papers, now republished in Chaco Astronomy: An Ancient American Cosmology .
Sofaer’s work has also included extensive educational presentations with schools, universities and archeological groups, as well as consultations with Pueblo educators who regard Chaco as a place with primary significance in their history.

In 1982 Sofaer produced, directed and co-wrote The Sun Dagger, an hour-length documentary narrated by Robert Redford and broadcast nationally by the Public Broadcasting Service (PBS). This film documents the Sun Dagger site’s intricate markings of the solar and lunar cycles with light patterns on spiral petroglyphs. The late Joseph Campbell and the late Alfonso Ortiz of Ohkay Owingeh express poignant insights into the Chacoans’ symbolic joining of the sun and moon.

In 2000 Sofaer produced, directed and co-wrote The Mystery of Chaco Canyon , an hour-length film also narrated by Redford and broadcast nationally by PBS and by the National Geographic Society on its international cable network. This film documents the solar and lunar alignments of the Chaco culture’s primary architecture and the cosmographic alignment of the Great North Road. Several archeologists and Pueblo people speak of the significance of these findings.

In 2010 Sofaer, with archeologist Richard Friedman, through the Solstice Project, recorded The Great North Road with lidar (aerial laser scanning). This effort, funded by a grant from the National Trust for Historic Preservation, precisely documented the Chacoans’ remarkably elaborate alignment to the North. It also affirmed the great efficacy of lidar to precisely record other Chaco “roads.” Following the Solstice Project’s nomination, the Great North Road is now designated as one of the “Eleven Most Endangered Sites” by the NTHP.

Currently Sofaer is producing and co-directing a third documentary Written on the Landscape: Mysteries Beyond Chaco Canyon to be broadcast by PBS and narrated by Robert Redford. The film will explore the great expanse of the Chacoan world --- a region of the American Southwest nearly twice the size of Ireland. It documents hundreds of miles of subtle and fragile linear alignments --- remarkably wide and straight --- that were once thought to be roads. In new revelations, the film shows how these alignments connect the Chacoans’ ceremonial Great Houses with places of power in the landscape. Archaeologists reveal evidence of their massive development for primarily ritual use. Pueblo and Navajo people give moving insights to their spiritual significance. Adriel Heisey’s magnificent aerial cinematography shows the sweeping expanse of the Chacoans’ works across one of the most challenging environments in the world. The film is co-directed with Matt Dibble who is also contributing his creative editing and cinematography.

Sofaer’s research findings have been presented in National Geographic, the Encyclopedia Americana, the journals Science and Science 80 of the American Association for the Advancement of Science (AAAS), Carl Sagan’s COSMOS, textbook Astronomy: From Earth to the Universe and Archaeology, Joseph Campbell’s Atlas of World Mythology, and many other academic volumes and journals.

Anna Sofaer and her husband Michael Pertschuk live and work today in Santa Fe, NM.



The Solstice Project, a non-profit group, was organized in 1978 to study, document, and preserve the remarkable Sun Dagger - a celestial calendar of the ancient Pueblo Indians.  It continues to study other achievements of ancient Southwestern cultures.

Read More about The Solstice Project's understanding of Chaco cosmology

Read an interview with Anna Sofaer


"The Solstice Project and Anna Sofaer give us a new view of Chaco Canyon and ancient North America correcting long- standing prejudices: the colonial insistence of savages on a continent that was, in fact, teeming with cities and civilizations.  America before 1492 was a complicated, cosmopolitan, interesting place.  Sometimes it takes a jolt or shock to open our eyes to reality, and the Solstice Project has been high amperage.”

-Stephen Lekson, editor,
The Architecture of Chaco Canyon, New Mexico

All material on this site is © 2016 The Solstice Project