Thanks to the exceptional transparency of its skies, northern Chile is home to the largest concentration of astronomical observatories in the world. The region around La Serena, in particular, has been chosen by a number of international astronomical research institutions as the site of their telescopes, housed in white, futuristic domes that loom over the valleys from their hilltop locations. Among the research organizations that own the observatories are North American and European groups that need a base in the southern hemisphere (about a third of the sky seen here is never visible in the northern hemisphere).
Some of the observatories offer guided tours, including the impressive Cerro Tololo Inter-American Observatory, whose 4m telescope was the strongest in the southern hemisphere until it was overtaken by Cerro Paranal’s Very Large Telescope, the most powerful in the world, located near Antofagasta. All the tours listed below take place during the day and are free of charge but are strictly no-touching; a more hands-on night-time experience is provided by the small but user-friendly observatory on Cerro Mamalluca, 9km north of Vicuña, as well as by the newer Del Pangue observatory 17km south of Vicuña and the Collowara observatory outside Andacollo.
Las Campanas 155km northeast of La Serena, 51 207301, lco.cl. The Carnegie Institute’s observatory contains four telescopes, with two 6.5-metre telescopes under construction as part of its Magellan Project. Contact the observatory’s offices in La Serena to make reservations; they’re located next to Cerro Tololo’s offices on Colina El Pino.
Cerro Tololo 88km east of La Serena, reached by a side road branching south of the Elqui Valley road, 51 205200, http://www.ctio.noao.edu. Tours need to be booked several days in advance; you’ll need to collect your visitor’s permit from the observatory’s offices in La Serena (up the hill behind the university, at Colina El Pino) the day before the tour.
La Silla 150km northeast of La Serena, reached by a side road branching east from the Panamericana, 2 4644100 in Santiago, 51 272601 in La Serena, eso.org. The site of the European Southern Observatory’s fourteen telescopes, including two 3.6m optical reflectors. Book tours in advance through the observatory’s Santiago offices or the La Serena office near the airport at Panorámica 4461.