Crab Nebula Supernova and the Aztec Culture

From Wikipedia:Aztlan

Legend 

Nahuatl legends relate that seven tribes lived in Chicomoztoc, or "the place of the seven caves"...Because of a common linguistic origin, those groups also are called "Nahuatlaca" (Nahua people). These tribes subsequently left the caves and settled "near" Aztlán, or Aztatlan

The various descriptions of Aztlán are seemingly contradictory. While some legends describe Aztlán as a paradise, the Aubin Codex says that the Aztecs were subject to a tyrannical elite called the Azteca Chicomoztoca.Guided by their priest, the Aztec fled, and, on the road, their god Huitzilopochtli forbade them to call themselves Azteca, telling them that they should be known as Mexica...

The role of Aztlán is slightly less important to Aztec legendary histories than the migration to Tenochtitlán itself. According to the legend, the southward migration began on May 24, 1064 CE; 1064 is also the year of a volcanic explosion at Sunset Crater in Arizona and the first Aztec solar year, beginning on May 24, after the Crab Nebula events from May to July 1054 (Supernova). Each of the seven groups is credited with founding a different major city-state in Central Mexico....

As their culture was so tied in with astronomy and the gods, I wonder the significance of this