THE ANCIENT ANDEAN CONCEPT OF CALENDAR.

The old cultures of the Andes thrust upward through some of the world's most forbidding terrain: the towering mountains and desert coast of the Andes. The empire of the Inca, which crowned them, ruled from a capital 11,000 feet in the clouds.
The ancient people of the Andes kept track of time with calendars which had ritual and religious meaning. While the Julian calendar came to the Andean territory in the 16th century, and Gregorian calendar in now in general use, only in a few communities now located in the Andean Highlands still use the ancient count of days and nights.
So little is know about the calendar used by the Inca, since no written language was used at the time, but it is widely believed that the "quipus" of the Inca contains calendrical notations based on the observation of both Sun and Moon and their relationship to the stars.
The Inca were sometimes said to be people of the sun, whereas the Aymara were sometimes said to be people of the moon.
The Constellation of the Southern Cross is a strong symbol of the ancient Andean cultures and is considered the most complete, holy and geometric design of the center of the universe, as they believe it was. It is to be seen on the Southern hemisphere and it is easy to find in a clear sky at night. The symbol is often found in old places and holy centers in the Andes of Peru and Bolivia.
The Andean people defined their territories and  recorded astronomical cycles with long-distance alignments which were measured out between the highest sacred mountains, lakes and lagoons. Localized alignments between cairns of stones were known as "saywas" which translates to "marker."
The Incas created 41 long-distance alignments called "ceque lines" which were oriented to significant solar, lunar and stellar occurrences, integrating astronomy and cosmology with their sociopolitical structure. These 41 energy lines were perceived as being imbued with sacred creation forces of energy that were aligned from the source and being channelled and emanated from the Coricancha, Temple of the Sun religious complex, in Cuzco.
The sun god Inti was worshiped most intensely at the winter solstice and still is today, every June 24, the Festival of the Inti Raymi. The hills surrounding the Inca's capital city Cuzco and the arrangement of massive pillars are a visible link to Inti, the sun god, who was thought to sit of the "saywas" at winter and summer solstices marking the sunrises and the sets.
Ancient Andean reality was and still is very different from western cosmology. The Andean universal outlook is based in the understanding that all forms possess male and female energies which flow along natural roads marked along the landscape of the Andean Mountains. It forms a superimposition of inner space on to the outer landscape. The Incas devised this natural and sacred language of opposite forces to design a great systematical organization, based on an superb and ordered study of astronomy aligned with a very detailed calendar.