Qualla: Cerro Tololo Inter-American Observatory

Cerro Tololo Inter-American Observatory: Introduction

Sun, 21 Jun 2026 00:00:00 GMT

Photo credit NOIRLab/NSF/AURA, CC BY 4.0. In the late 1950s an astronomer named Jürgen Stock climbed the mountains east of La Serena on muleback, hauling a small telescope and an interferometer up slope after slope, measuring the steadiness of the air and the clarity of the light. He was hunting for the darkest, stillest sky in the southern hemisphere. On 23 November 1962 the search ended on a 2,200-meter summit called Cerro Tololo, and the observatory that took its name has been mapping the southern stars ever since.

Image: NOIRLab/NSF/AURA | CC BY 4.0

Cerro Tololo Inter-American Observatory: The Edge of the Abyss

Sun, 21 Jun 2026 00:00:00 GMT

Photo credit CTIO/NOIRLab/NSF/AURA/D. Munizaga, CC BY 4.0. 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...

Image: CTIO/NOIRLab/NSF/AURA/D. Munizaga | CC BY 4.0

Cerro Tololo Inter-American Observatory: The Great Eye of Blanco

Sun, 21 Jun 2026 00:00:00 GMT

Photo credit CTIO/NOIRLab/NSF/AURA/B. Tafreshi, CC BY 4.0. 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. I...

Image: CTIO/NOIRLab/NSF/AURA/B. Tafreshi | CC BY 4.0

Cerro Tololo Inter-American Observatory: Discoveries in the Dark

Sun, 21 Jun 2026 00:00:00 GMT

Photo credit Chile_location_map.svg: NordNordWest derivative work: Виктор В (talk), CC BY-SA 3.0. 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. ...

Image: Chile_location_map.svg: NordNordWest derivative work: Виктор В (talk) | CC BY-SA 3.0

Cerro Tololo Inter-American Observatory: A Cluster of Summits

Sun, 21 Jun 2026 00:00:00 GMT

Photo credit NOIRLab/AURA/NSF, CC BY 4.0. 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 tel...

Image: NOIRLab/AURA/NSF | CC BY 4.0