Ancient astronomy: Looking at the Sky through the eyes of the Inca


Ancient astronomy: Looking at the sky through the eyes of the Inca

Inca view of the milky wayThis painting shows some of the animal shapes that the Incas saw in the dark spots of the Milky Way
Photo by Koricancha Sun Temple/Cusco

Gazing up at a starry night sky is nothing short of magical. People have long been fascinated with stars, and have attempted to find meaning in what they saw in the sky. The Inca civilization in Peru placed a great importance on astronomy. They were the only culture in the world to define constellations of both light and darkness. The Incas however not only identified constellations and individual stars, but they also assigned each a purpose. They believed that everything in and around our world was connected. How else did the sky impact this great civilization?

The complex Inca belief system

The Inca flourished in the Andes Mountains in South America from the 12-16th centuries. They had a grand empire stretching from present-day Colombia to Chile. Worship was very important to them and they had a complicated religion, closely linked to astronomy. The Inca worshiped various Gods, including Viracocha (the creator) Inti, (the sun), and Chuqui Illa, the God of thunder. They also worshiped huacas, spirits that were believed to inhabit any remarkable phenomenon, including large boulders, trees, streams or waterfalls.

The creator ViracochaA visual depiction of the Creator – Viracocha
Wikimedia Commons

In general, the sky was very important to the Inca. Both the moon and sun were seen as God and they built extravagant pillars and temples with great precision so that these “heavenly bodies”, like the sun, would pass over the structures or through windows on specific days, like the summer solstice. The most crucial events for the Inca generally involved the rising and setting of the sun, moon, and stars.

Machupicchu intihuatanaBuilt by the Incas, this is the Temple of the Sun, Machu Picchu
Photo by Fabricio Guzmán/Wikimedia commons

Astronomy was very important for the Inca civilization, partly due to the importance of agriculture. Astronomy was  used for agricultural purposes.  Cuzco for example lies on a radial plan, mimicking the sky and pointing to specific astronomical events on the horizon. Similarly to the ancient Egyptians, this was a horizon-based culture. They built carefully placed pillars on mountains and hills overlooking Cuzco, so when the Sun rose or set between these pillars, they knew they had to plant at a specific altitude.

The Inca however not only studied individual stars, but also grouped stars into constellations.

The Inca Constellations: Darkness and light

Upon looking at the stars, the Inca noticed many animals and things from their day to day lives. They believed that Viracocha had ensured that each animal or bird had a corresponding star and that all living things would be protected. Grouping these stars into constellations became very important to the Inca.

The Inca sorted the constellations into two groups. The first is most common: groupings of stars that are linked in a connect-the-dots manner to create pictures of animals, Gods, heroes and more. These constellations were considered as inanimate. One star grouping known as Pleiades was especially believed to be influential over the well-being of animals. Pleiades was not seen as a greater God to the Inca, but they rather saw it as a huaca to which the Shamans would make regular sacrifices.

Southern Night Sky along the Inca Trail.A view of the night sky from the Inca Trail
Photo by Steve Manders/Panoramio

The second type of constellations could only be observed when there were no stars: they were the dark spots or blotches on the Milky Way. These dark blotches were considered as living (animate) animals. The animals were believed to live in the Milky Way, which they thought of as a river. The Inca were one of the few civilizations who were able to locate their constellations without the presence of stars.

Here are some of the animal constellations they identified:

  • Mach’acuay – the Serpent
  • Hanp’atu – the Toad
  • Yutu – the Tinamou
  • Urcuchillay – the Llama
  • Atoq – the Fox

The worship of constellations by the Inca culture, and the knowledge of their importance in the agricultural cycle, managed to survive Spanish conquest and the colonial era.

Giving these findings a meaning: All is connected

The Inca worship of stars and dark constellations shows us that this culture believed everything around them was connected. The sky had a very special meaning in managing this civilization and impacted day to day life. Even the construction of the famous Machu Picchu site is connected to the stars. Archaeological and ethnological studies now suggest that Machu Picchu was a sacred ceremonial site, an agricultural experimentation center, and an astronomical observatory.

Inti RaymiA recreation of the Inca Festival of the Sun – Inti Raymi – at Sacsayhuaman, Cusco
Photo by Cyntia Motta/Wikimedia Commons

In his book, Animals and Astronomy in the Quechua Universe,  Urton says “The universe of the Quechuas is not composed of a series of discrete phenomena and events, but rather there is a powerful synthetic principle underlying the perception and ordering of objects and events in the physical environment.” (pg. 126). The snake that they for example saw in the sky has the same cycle as snakes on earth, and both live in harmony, alongside the other celestial animals. This is contrary to traditional Western constellations, where various images (i.e. Scorpion, Scale, Fish etc.) have no interaction with each other or things happening on earth.

Much remains to be uncovered about the importance of constellations to the Inca. Researchers continue to do fieldwork in rural Andean communities where one can still look up at the same constellations that the ancient Incas gazed at centuries before.

Where and when can you get immersed in Inca astronomy?

Interested in a stargazing adventure in Cusco? Want to see what the Inca saw? We recommend you make your visit outside the rainy season (which goes from November to March), as Cusco stargazing (probably) isn’t that great during this time of year.

We highly recommend you visit the Cusco Planetarium – a center studying the Inca world view through the skies. The center highlights that the Inca’s took the study of astronomy very seriously! Try to go to the Planetarium before you trek the Inca Trail – you will feel extra smart having the ability to point out the Llama in the sky to the other hikers! Remember: reservations are essential. Prices are usually around 30 Soles (about $10) but depend on group size, and generally include both pick-up and drop-off.

Plan a star-gazing Cusco adventure in Peru!

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Inti Raymi in Cusco


About Author

Hendrika is Belgian but she considers herself a citizen of the world as she has lived in many different countries before moving to Peru. She fell in love with South America after her first visit to the continent in Bolivia, and has since then spent a lot of time traveling in the area. She especially enjoys Peru for its diversity, delicious food, and rich history.

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