Mountaintop Neighbors

Two world-class astronomical sites are seen in this aerial sunset image captured in northern Chile. In the foreground is NSF–DOE Vera C. Rubin Observatory, jointly funded by the U.S. National Science Foundation (NSF) and the U.S. Department of Energy (DOE) Office of Science. Rubin Observatory is located on Cerro Pachón at an altitude of 2600 meters (8600 feet). In the distance to the right of Rubin Observatory is the mountaintop Cerro Tololo, home to the NSF Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. The structure at the top of Cerro Tololo is the Víctor M. Blanco 4-meter Telescope, located at an altitude of approximately 2200 meters (7200 feet).

Together Cerro Pachón and Cerro Tololo form a major astronomical observation hub. Their high-altitude locations provide astronomers with an abundance of cloud-free nights with dry, stable air — when the occasional clouds do form, they contribute to beautiful sunsets like the one captured here.