Successor to the European Organization for Astronomical Research in the Southern Hemisphere, the European Southern Observatory (ESO) represents 16 nations collaborating on ground based astronomical research. At a 1962 Convention, the ESO announced its primary mission, to “provide state-of-the-art research facilities to astronomers and astrophysicists, allowing them to conduct front-line science in the best conditions.” The ESO staff 700 employees and receives over 198 million Euros in contributions annually. On top of performing some of our civilization’s great scientific experiments and observations, the ESO develops and constructs generation after generation of advanced technology, continuously surpassing the boundaries of human endeavor while enabling the greatest minds in the world to further our knowledge and understanding of the Cosmos with each new discovery. Headquartered in Garchin near Munich, Germany, as of 2019 its member states include Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Chile hosts the European Southern Observatory in several locations in the Atacama Desert.

Image composition showing all the ESO observatories and the Headquarters, with a spiral arm of the Milky Way Galaxy in the backdrop. Credit: ESO/M. Kornmesser

The La Silla Observatory, located in a remote region north of Santiago at an altitude of 2400 meters, offers one of the darkest skies on Earth, allowing for breathtaking and unobstructed observations. It is the ESO’s first site, established in 1964 and remains one of mankind’s more prominent astronomical facilities. 

It is famously the first telescope equipped with computer controlled main mirror, which set the standard for international space observations, as most observatories adopted this same technology, now utilizing it all around the world. At La Silla, the ESO’s 3.6-metre telescope famously houses the planet hunter HARPS, a spectrograph with advanced precision responsible for many of mankind’s exoplanet discoveries. La Silla sports a remarkable top ten list, with notable mentions including the discovery of a potentially habitable world in the Proxima Centauri star system (our closest interstellar neighbor),  proving that the Universe expands at an accelerated rate, and the existence of stars orbiting the Milky Way’s center super-massive black hole. 

Sprites, irregularities in the ionosphere, photohraphed in the skies above La Silla. Credit: P. Horálek/ESO

The Paranal Observatory, which houses the Very Large Telescope (VLT), rests at an altitude of 2600 meters in the region of Cerro Paranal, 130km south of Antofagasta. Paranal serves as the European Southern Observary’s flagship facility, offering the most scientific productivity and research than any similar destination. Parnal opened its doors in 1999, utilizing the VLT to perform some of humanity’s most successful research programs. Here, astronomy thrives. The VLT uses the most advanced technology currently available in astronomy, comprised of an array of four individual telescopes, allowing for observations with pristine detail of some the universe’s most distant objects.

The third component of the ESO resides in the Antogasta Region of the Atacama Desert, called Chajnantor Observory where the Atacama Large Millimeter Array (ALMA) operates. A total of 66 radio telescopes compose ALMA at 5000 meters in elevation, making it one of the highest astronomical observatories on Planet Earth and the largest ground based space project ever created.

The ESO remains busy at work developing the 39-meter Extremely Large Telescope (ELT), poised to become Planet Earth’s “biggest eye on the sky.” 

Aerial view of the observing platform on the top of Cerro Paranal, with the four enclosures for the 8.2-m Unit Telescopes (UTs) and various installations for the VLT Interferometer (VLTICredit: ESO

ALMA at night. Credit: ESO

The European Southern Observatory’s primary facilities in Chile. Credit: ESO