Cerro Tololo sits roughly 80 kilometers east of La Serena, where the coastal haze falls away and the Andes climb into some of the driest air on the planet. Construction began in 1963 with Stock as the first director, and the first regular observations came in 1965. The conditions are extraordinary: hundreds of cloudless nights a year, thin dry atmosphere, and almost no light pollution for hundreds of kilometers. What looks from below like an ordinary brown ridge is, after dark, one of the finest windows onto the universe that Earth provides.

The mountain's flagship is the Víctor M. Blanco Telescope, a four-meter giant whose mirror weighs some 34,000 pounds. Assembled on the summit in 1974, it was named in 1995 for Víctor Manuel Blanco, the Puerto Rican astronomer who directed the observatory for nearly two decades. In 2012 it gained a new heart: the Dark Energy Camera, a 570-megapixel instrument that captured its first light on 12 September that year. With it, the Dark Energy Survey charted some 5,000 square degrees of sky — roughly one-eighth of the entire celestial sphere — chasing the invisible force that is pushing the cosmos apart.

Great instruments find strange things. In 1985, working from sky photographs taken on Tololo, support technician Arturo Gomez spotted a peculiar object that turned out to be a young star wrapped in a disk of dust — forever after known as Gomez's Hamburger, for its layered shape. Decades later, on a December morning in 2013, a research assistant at the University of Chile named Luis González caught a supernova in a galaxy 370 million light years away. It was the first discovery by a robotic Chilean telescope on the mountain, confirmed by astronomer José Maza, proof that the country had grown its own generation of star-hunters.

Tololo no longer works alone. About ten kilometers to the southeast rises Cerro Pachón, home to the 4.1-meter Southern Astrophysical Research Telescope and, more recently, to the giant survey observatory that will scan the entire visible sky night after night. Smaller robotic telescopes from networks around the world dot these ridges, all of them drawn by the same gift: the clarity that Jürgen Stock measured on muleback more than sixty years ago. This corner of the Andes has become, quietly, one of the astronomical capitals of the world.