Casa Rinconada
Casa
Rinconada is one of the six great community kivas in the Chaco Canyon
area. Built on an isolated hill on the canyon's south side 1/2 a mile
across from Pueblo Bonito and Chetro Ketl, the ceremonial structure is
about 20 meters (63.5 ft) in diameter and 4 to 5 meters deep.
Asserted
to be a physical representation of the Anasazi cosmos by archaeologists
and anthropologists, it was found to have precise solstices and equinox
alignments in a 1970's survey of the area. Dr. Ray Williamson, then an
astronomer with OTA for the US Congress, and his colleagues Howard J.
Fisher and Donnel O'Flynn have done extensive research of Chaco Canyon
sites and much of our current archaeoastronomical knowledge of Casa Rinconada
can be attributed to them.
Casa Rinconada has a main axis which is aligned to true cardinality along
a north south line passing through the centres of the north and south
doorways. This north south axis has an azimuth of 359°56'. If you
connect each wall regular wall niche to the one opposite it, you will
find that all but one of them pass within 10 cm of the kiva centre, meaning
that the kiva is a model of a perfect circle. One of these lines has an
azimuth of 89°52' and establishes an east west line. According to
archaeoastronomer E. C Krupp, these features are tied to the order of
space and the direction of time.
In addition, the precision of these measurements and constructions are matched at Pueblo Bonito (above), a massively built mountain stronghold in the shape of a D, where Dr Williamson found that the central plaza, is bisected by a low wall on a north south line. The wall falls short of an exact north south alignment by only 45 arc minutes, or 3/4 of a degree, while the west half of the south wall is orientated east wes with an error of 8 arc minutes south of east.
The fascination of Casa Rinconada springs from two sets of unusually uniform wall niches in the kiva. These consist of 28 regularly spaced compartments and 6 larger irregularly spaced niches, 2 of which are on the eastern side of the wall and 4 on the western side. When sunlight enters the kiva, it falls upon one of the 6 irregular niches lower on the wall than the others next to it. From that niche, the sun is framed in the narrow compartment on the northeast side of the kiva. On the winter and summer solstices, this illumination of niche effect and framing of the sun in a compartment would have been apparent to the observer.
The
problems and twists to this site lie in a number of factors. Firstly,
the walls of the kiva are built higher than the surrounding ground level,
which would have prevented any light from entering it. Secondly, the upper
part of the west wall was in ruin when the kiva was excavated, and we
are not sure of its original structure. Thirdly, the position of the northwest
roof post, would have blocked any light from illuminating the wall niche.
The northeast window's function which we see today may therefore either
have been an accident or an improvement made during evident reconstruction
during historic times.