The Aztec Horoscope. The Aztec year began in February, they also had three types of calendar. The solar year, that had 365 days, but was divided by them in twenty months of twenty days each one, and with five extra days.The sacred year with 260 days, divided in twenty signs multiplied by thirteen.he Aztec Horoscope. The Aztec year began in February, they also had three types of calendar. The solar year, that had 365 days, but was divided by them in twenty months of twenty days each one, and with five extra days.