from what i heard i believe they used a floral calendar so to figure out which one corresponds to you, you need to know how to make a floral calendar work for the place you were born. Lords of the Day 1st Lord - Xiuhtecuhtli/Huehueteotl (as god of fire) 2nd Lord - Tlaltecuhtli (as earth god) 3rd Lord - Chalchiutlicue (as water goddess) 4th Lord - Tonatiuh (as sun god) 5th Lord - Tlazolteotl (as goddess of love) 6th Lord - Teoyaomiqui/Mictlantecuhtli (as god of fallen warriors) 7th Lord - Xochipilli-Centeotl (as god of pleasure/maize) 8th Lord - Tlaloc (as god of the rains) 9th Lord - Quetzalcoatl (as god of the winds) 10th Lord - Tezcatlipoca (as god of sustenance) 11th Lord - Mictlantecuhtli/Chalmecatecuhtli (as god of the underworld) 12th Lord - Tlahuizcalpantecuhtli (as god of the dawn) 13th Lord - Ilamatecuhtli (as goddess of the sky) Lords of the Night 1st Lord - Xiuhtecuhtli/Huehueteotl (as god of fire) 2nd Lord - Itztli (as god of obsidion/flint) 3rd Lord - Piltzintecuhtli-Tonatiuh (as the youthful sun god Piltzintecuhtli-Xochipilli) 4th Lord - Centeotl (as god of maize) 5th Lord - Mictlantecuhtli (as god of the underworld) 6th Lord - Chalchiutlicue (as water goddess) 7th Lord - Tlazolteotl (as goddess of love) 8th Lord - Tepeyolohtli-Tezcatlipoca (as the heart of the mountain) 9th Lord - Tlaloc (as god of the rains)
well you would have to probably find out the plants that were used in their floral calendar (if this truely was their basis for time keeping) through research. the plants that were native to their area that had constant traits like opening at a certain time of day may be relevent, but maybe they used the sun to tell time. is their a archeologist who knows about the aztec on this board? my advise, find someone who knows alot about ancient aztec culture.
