San Cosme y Damián also preserves an extraordinary astronomical legacy. In the early 18th century, Father Buenaventura Suárez built here the first colonial observatory in South America. With telescopes he crafted himself with the help of the guaraní, he made calculations and eclipse predictions that astonished European scientists.

Today, the center offers a planetarium that blends science with guaraní cosmovision, solar and night telescopes, and an astrolabe that recreates the movement of stars and constellations like a mechanical computer. In the Mission’s courtyard, a remarkably precise sundial carved in stone still remains as testimony of that first observatory.

But the experience goes beyond the daytime. At night, San Cosme’s sky reveals itself in all its splendor. Far from any light pollution, the Milky Way and constellations appear with striking clarity. The observatory remains open every night, offering stargazing as an emotional and unforgettable journey.