Calendar became after kalendas, which was the first day of the roman´s months. The main use of the old Mayan and Egyptian "calendars" was to adequate the nature cycles with some civilian issue, this natural cicle was the tropic year, time which take the earth to make a complete cycle around the sun, or the orthoheliacus movement of Sirio star in the case of egyptians.

So, the must important and survival issue was to determine how log was that cycle long. This is the first and more important time issue ever. And, for a priest, always a priest, was easy to do it, just watch the horizon.

In the peculiar case of my Cosmic Room, you can see the Pueblito Pyramid a short distance far, and you will note in the winter solstice the sun falls exactly, exactly, this is not a photoshop picture, over the pyramide, watching from roof, stays for a few days, that´s why is the solstice, after statio, park. 

So, this extraordinary coincidence (if we can call it so) make the Cosmic Room very special.

And folowing the sunsets we can observe a very big and natural calendar, lets see the pictures:

 

January 29th

 

February 2nd

 

February 18th

 

February 28th

 

April 13th

 

May 7th

 

June 1st

 

As you can see is simple and extraordinary.

Folowing with my Cosmic Room you can see the analemma is also a calendar:

 

 

And also my projective sundial is a calendar:

You can see dating on the meridian line.

 

The length of the beam line marks a date. So this is also a calendar, but, as you an see I prefer the big pyramid one. And I can see it every year at the roof of this very special place.