ALMA Observatory

ALMA — The Eyes of Humanity

The Atacama Large Millimeter/submillimeter Array (ALMA) is the most expensive and powerful ground observatory in the world — a joint project by Europe (ESO), North America (NRAO), and East Asia (NAOJ), which cost over 1.4 billion US dollars. The 66 radio telescope antennas (each 12 or 7 meters in diameter, weighing up to 115 tons) are located on the Chajnantor Plateau at 5,050 meters altitude — one of the highest observatories in the world.

ALMA observes the universe in the millimeter and submillimeter wavelength range — wavelengths between infrared and radio waves. This allows ALMA to see things invisible to optical telescopes: The birth of stars and planets in dense gas and dust clouds, the chemical composition of distant galaxies, and the oldest structures in the universe. In 2019, ALMA was part of the network that took the first photo of a black hole.

Visiting

Every Saturday and Sunday, ALMA offers free tours (advance registration on the ALMA website required, booked out months in advance!). The visit leads to the Operations Support Facility (OSF) at 2,900 m — not to the Chajnantor Plateau itself (5,050 m, too high for unacclimatized visitors). There you can see the control rooms, visit an antenna replica, and learn about current research from astronomers.

Other Observatories

• Paranal Observatory (ESO): The Very Large Telescope (VLT) with four 8.2-m mirrors — one of the most powerful optical telescopes in the world. Free Saturday tours, registration via ESO website. 120 km south of Antofagasta
• Extremely Large Telescope (ELT): Under construction on Cerro Armazones — with a 39-meter mirror diameter, it will be the largest optical telescope in the world. Completion expected in 2028
• SPACE Observatory (San Pedro): Private observatory for tourists with high-quality telescopes. Evening astronomy tours, highly recommended (25,000–35,000 CLP)