Chaco Canyon · Archaeoastronomy · ephem · forge3d · Leaflet
☀️ SOLSTICE
A live archaeoastronomy dashboard watching the same sky, over the same canyon, that the Chacoan people built their great houses to track. Current sun and moon positions computed for Chaco Canyon twice daily. Live alignment monitor for the Casa Rinconada northeast doorway — the great kiva whose entrance aligns to the summer solstice sunrise at 66.5°. Days to the next solstice and equinox. Interactive Leaflet map with all ten great houses and the Chacoan road network.
The terrain hero is a GPU-rendered 4K hillshade of Chaco Canyon from USGS 3DEP 1/3 arc-second LiDAR data, rendered via forge3d — camera southeast of the canyon looking northwest, late-afternoon sun casting shadows into the mesa cuts. Pueblo Bonito's rear wall runs true north within 0.1°. Casa Rinconada's alignment activates in the dashboard when the current sunrise azimuth falls within 3.5° of 66.5° — around the summer solstice window each June.
| Site | Rooms | Period | Notable |
|---|---|---|---|
| Pueblo Bonito | ~800 | 850–1150 CE | Rear wall faces true north within 0.1°. Largest great house in the canyon. |
| Chetro Ketl | ~500 | 1010–1110 CE | Unique colonnade. 4 stories. One of the finest examples of Chacoan masonry. |
| Casa Rinconada | — | 1000–1100 CE | Great kiva. NE doorway aligns to summer solstice sunrise at 66.5°. SOLSTICE alignment anchor. |
| Pueblo del Arroyo | ~280 | 1075–1115 CE | Adjoins rare tri-walled structure. Late occupation. |
| Hungo Pavi | ~150 | 900–1100 CE | Largely unexcavated. Two great kivas. Spring equinox alignments documented. |
| Una Vida | ~160 | 850–1000 CE | One of the earliest great houses. Nearby petroglyphs including possible supernova pictograph. |
| Penasco Blanco | ~150 | 900–1125 CE | Near the possible 1054 CE supernova pictograph — a painted hand, crescent, and bright disc. |
| Pueblo Alto | ~90 | 1020–1100 CE | Mesa-top terminus of the Great North Road — 50 miles straight across the mesa with no practical purpose. |
| Kin Kletso | ~55 | 1125–1150 CE | Late McElmo-tradition construction. One of the last great houses built. |
| Wijiji | ~90 | 1100–1150 CE | Easternmost great house. Accessible only by foot trail. |
The Alignment at Fajada Butte
On Fajada Butte, three stone slabs leaning against a cliff face create daggers of light that bisect spiral petroglyphs at every solstice, equinox, and major lunar standstill over an 18.6-year cycle. This solar marker was documented by artist Anna Sofaer in 1977 — she returned during summer solstice and watched a dagger of light bisect the center of the spiral at noon.
The great north road leaves Pueblo Alto and runs straight for fifty miles across the mesa, cutting through arroyos and climbing ridges with no apparent practical purpose. As if it wasn't built for walking, but for seeing — a line drawn from a specific point toward something on the horizon that mattered.
Project Kiva — LiDAR Pipeline
SOLSTICE's companion project — Project Kiva is a Southwest archaeology remote sensing pipeline using real USGS 3DEP LiDAR data. Sky-View Factor, Local Relief Model, and automated feature detection across Chaco Canyon, Mesa Verde, Hohokam Phoenix, and Canyon de Chelly.
The same LiDAR data that renders SOLSTICE's terrain hero also feeds Project Kiva's archaeological feature detection. The 1/3 arc-second DEM strips the vegetation and modern disturbance away and reads the landform underneath — walls, roads, kivas — that have been invisible to surface survey for generations.