Great houses and the sun - astronomy of Chaco Canyon

The primary axes of Basketmaker III pit structures at Shabik'eschee in Chaco Canyon have two orientations, one to the south and the other to the south-south-east. This architectural tradition continued with remarkable continuity throughout the San Juan Basin to the end of Pueblo III. Many of the Great Houses in Chaco, which appear to be massively enlarged front-facing unit pueblos typical of the Northern San Juan, continued this tradition. Orientations of the back walls of Great Houses to the solstice sun or standstill moon may never have been intended by the builders. Claimed inter-site alignments of Great Houses to minor or major standstill limits appear to be the results of local topography and not intended by the builders. Late Bonito phase (AD 1100–1140) Great Houses are distinguished by their planned designs, relatively short construction period, and negligible middens. Solstice sunrise or sunset horizon foresights are present at the majority of these Great Houses, which may have been designed in part to provide demonstrations of the astronomical knowledge of the Chacoan leadership