The observatory at Chichen Itza, also known as El Caracol, is a circular structure very similar to those found in other parts of Mesoamerica. The observatory is a building constructed as a large round tower set on a platform with a central staircase. Through the upper observation windows, one can see the equinoxes, sunsets, solstices, the position of Venus and other stars, and the results of these observations influenced many decisions and actions taken by the ruling class. The main purpose of the observatory at Chichen Itza was to observe and study the trajectory of Venus’s movement, and based solely on visual observations, the Maya learned that: Venus appears in the west and disappears in the east at different times throughout the year, its synodic cycle lasted 584 days, 5 Venus cycles were equivalent to 8 solar years, and Venus appeared at the northern and southern poles at intervals of 8 years.

The principle of astronomical observations is based on two angles of the walls inside the opening; this method allows observations to be made with great accuracy. Studying the results provided by the upper chamber of the observatory at Chichen Itza, we obtain the following results:

·      The first observation period gives us an exact direction to the south.

·      The second — the setting of the Moon on March 21.

·      The third — the direction to the west, as well as the sunset on the equinox days of March 21 and September 21. And finally, the second observation through the same place corresponds to the sunset on the day of the summer solstice, June 21.

The Maya studied the Sun, Moon, and Venus, and their observations included some visible bodies such as Mercury, Mars, and other stars. Their priests, the greatest astronomers of their time, excelled in calculating solar and lunar eclipses, the rising and setting of Venus, the movement of stars and planets, as well as the solar year with great accuracy. Even today, scientists are amazed by the development of Maya astronomy. For the ancient Maya, astronomy and cosmogony were closely linked in their mythical concept of the Universe. Known as the “Lords of Time,” the Maya were unique in elevating not only the idea of time but also the periods into which it is divided to the rank of gods. They represented time as supernatural beings whose mission was to maintain order in the Universe. The life cycle of the Maya Gods of time was a constant circular motion, beginning with their birth, developing with the manifestation of their characteristics, and ending with their death. Then they were reborn, and a new cycle of births and deaths began.

The observatory was also used to determine the dates of sacred rituals and to define agricultural cycles because the time of sunset on the horizon marked important stages of the annual cycle and, therefore, shows not only the ritual but also the economic importance that observatories had for the Maya.

The building consists of a rectangular platform measuring 67 m from north to south and 52 m from east to west; it has a single body with a slightly sloping cornice, with a total height of 6 m. On its facade, there is a set of 3 staircases pointing west and decorated with intertwined snakes. On it, a circular building 16 m in diameter and 5 m high was built on top of the main platform with a single body consisting of sidewalks with a small protruding molding and a vertical wall topped by another molding. In addition, a structure 11 m in diameter and 3.70 m high was erected, consisting of a single vertical body between two molded cornices.

The third and upper body is heavily damaged, but a series of small openings or portholes used for observations can be seen on it. A rectangular platform with a staircase, limited by rafters decorated with feathered snakes, was attached to the southwest corner of the large platform of the observatory. On top of this platform, a temple or residential building 14 m long and 9 m wide was built, consisting of two parallel compartments, the first of which has two rows of columns, and the second is narrower with an entrance door that has a bench occupying almost the entire space. The facade of the building has a slope, a vertical wall, and a cornice with stucco, all without decoration.

The first part of the cylindrical tower is formed by two concentric walls surrounding a pair of round chambers, each with four doorways. The second level includes the cornice of the first level and a second, narrower one that frames the frieze. On the frieze above the doors are depicted the mask of Chaac and a seated figure, framed by motifs of feathers and snakes. The third and fourth parts of the tower have fallen into disrepair, but a series of openings or windows can still be seen, which possibly served for astronomical observations. On the western side of the larger base is a staircase whose balustrades are decorated with intertwined snake heads. The total height of the monument is about 23 meters. The structure was built during the first period of the city’s existence.

The observatory at Chichen Itza is located in the central group between Chichanchob and the House of the Nuns.

Sources:

https://mayanpeninsula.com/en/observatory-chichen-itza/

https://www.chichenitza.com/el-caracol