Just the facts, please

Bloggers,

I've discovered a few blogs that deal with the Aztec or Mayan calendar that are mostly about the superstitious and prophetic side of it.

I'm more interested in the facts. What did these ancient people understand about astronomy and time, how did they know it, and how did they record it? I would like to know more about the research done on the codices to come to the conclusions or suppostitions that we have about the calendar.

DataLight