Peñasco Blanco

Construction of Peñasco Blanco may have begun around AD 900, making it one of the first large pueblos in the canyon. Additional building continued until about 1095. The ruin shows development in Chacoan masonry style from more primitive slab walls, through banded walls to rubble core and veneer seen in later Bonito Phase great houses.
Not far from Peñasco Blanco is the pictograph panel containing a crescent moon, a ten-pointed star, handprint, and a sun sign which has so caught the imagination of astronomers. The possibility that the panel represents the supernova of A. D. 1054 was considered by the
archaeologist Florence Hawley Ellis and others in the fall of 1972 and
initiated much of the interest in Chaco Canyon among astronomers. The
symbols are similar to those painted on a pillar marking a Zuni
sunwatching station described by Cushing, and sunwatchers may have been in place in the July morning of 1054 to view the supernova.
On the vertical face beneath these pictographs is a set of three
concentric circles with apparent flames extended horizontally to the west, which may be a representation of the A. D. 1066 appearance of Halley's comet, which was sufficiently impressive at that time to alarm the Saxon king prior to the Battle of Hastings.