This is a version of the article which appeared in EarthSky: Astronomy ambassadors in Chile: Cerro Pachón and Cerro Tololo

About an hour’s flight north of Santiago near the city of Vicuña, in the Equi Valle, lie some of the world’s best sites for observatories: Cerro Pachón and Cerro Tololo. Vicuña, in the Elqui Valley, calls itself the world capitol of astronomy, with many tourist and research observatories nearby. The ACEAP (Astronomy in Chile Educator Ambassador Program) cadre was treated to a night of stargazing at the lovely Alpha Aldea and learned about the many educational programs that they support.

Nearby, the 2019 ACEAP expedition was given full access to both the Gemini South and Cerro Tololo Interamerican observatory and spent two nights with the astronomers at CTIO.

Gemini South with the LSST to the right Credit R Pettengill (NRAO/AUI/NSF)

Cerro Pachón is the newer facility including the 4 meter (13 foot) SOAR (Southern Astrophysical Research) telescope, 10 m Gemini South, and under construction the 8.4 m (28 ft) LSST (Large Synoptic Survey Telescope). The Gemini telescope is the southern skies twin to the Gemini on Mauna Kea in Hawaii. Both SOAR and Gemini use adaptive optics correcting for atmospheric turbulence with sodium laser guide stars.

Nearby, Cerro Tololo hosts most of the U.S. National Science Foundation and National Optical Astronomy Observatory facilities. Cerro Tololo is ground zero for astronomical collaboration between the U.S. and Chile.

CTIO 1.5 m with ACEAP 2019 Credit: K Flores/C Johns (NRAO/AUI/NSF)

Professor Federico Rutllant of the University of Chile collaborated with AURA (Association of Universities for Research in Astronomy) to identify a site for a large Chilean American telescope in 1959 with the 1.5-meter (5-foot) telescope completed in 1965. The 4-meter (13 ft) telescope completed in 1976 and named for Puerto Rican astronomer Victor Blanco is now the CTIO’s largest.

Blanco telescope, Credit L Sparks (NRAO/AUI/NSF)

The profound darkness and silence of these sites at night is broken only by the deep hum of the telescopes dancing with the stars. We were treated to spectacular views of the Milky Way and the Magellanic Clouds.

Magellianic Clouds at the CTIO Blanco Telescope, Credit R Pettengill (NRAO/AUI/NSF)

Daytime at the observatories were filled with talks and questions. Our meals at the cafeteria (casino to Chileans) were good with spectacular vistas.

Cerro Tololo Casino Vista, Credit R Pettengill (NRAO/AUI/NSF)

We are headed next to San Pedro de Atacama and up to the ALMA radio telescope at 16,500 feet elevation.

For more about this trip, more images, and press articles see: ACEAP 2019 or #ACEAP2019 #AstroAmbassadors #NSFfunded on social media.