European Southern Observatory facts for kids

Quick facts for kids
European Organisation for Astronomical Research in the Southern Hemisphere

(L–R): ESO logo; Map of member states
Abbreviation	ESO
Formation	1962; 63 years ago (1962)
Type	Intergovernmental organisation
Purpose	Research organisation for astronomy
Headquarters	Garching, Germany
Membership	16
Official language	English, French, German
Director General	Xavier Barcons

The European Organisation for Astronomical Research in the Southern Hemisphere, usually called the European Southern Observatory (ESO), is a special group of 16 countries working together. Their main goal is to study space using powerful telescopes on the ground. ESO was started in 1962. Since then, it has given scientists amazing tools to explore the southern sky. Over 750 people work for ESO. Each year, member countries contribute about €162 million to help with research. ESO's main observatories are located in northern Chile.

ESO has built and runs some of the biggest and most advanced telescopes in the world. These include the 3.6-meter New Technology Telescope, which was one of the first to use smart mirrors that can change shape. Another famous one is the Very Large Telescope (VLT). It is made of four huge 8.2-meter telescopes and four smaller ones. They can work together or on their own. The Atacama Large Millimeter Array (ALMA) looks at the universe using special light waves called millimetre and submillimetre waves. It is the biggest ground-based astronomy project ever built. ALMA was finished in March 2013. Many countries from Europe, North America, East Asia, and Chile worked together on it.

Right now, ESO is building the Extremely Large Telescope (ELT). This telescope will have a giant mirror, almost 40 meters wide. It will be the world's largest optical telescope when it starts working later this decade. The ELT will be so powerful that it can study planets around other stars in great detail. It will also help us learn about the first objects in the universe, huge supermassive black holes, and the mysterious dark matter and dark energy that make up most of the universe.

ESO's telescopes have made many important discoveries. They have also created several astronomical catalogues. Some of their findings include discovering the most distant gamma-ray burst. They also found strong evidence for a black hole at the center of our own Milky Way galaxy. In 2004, the VLT took the first picture of a planet outside our solar system. This planet, called 2M1207b, orbits a brown dwarf star 173 light-years away. The HARPS instrument on ESO's 3.6-meter telescope helped find many other extrasolar planets. One of these was Gliese 581c, one of the smallest planets ever seen outside our Solar System.

How ESO Started

The ESO headquarters in Garching, Germany, in 1997

The same site in 2014, a year after a new extension was built (in the foreground)

The idea for a big European observatory came from astronomers Walter Baade and Jan Oort in 1953. They thought it would be great for European scientists to work together. On January 26, 1954, astronomers from six European countries signed a paper. They wanted to build a joint observatory in the southern part of the world.

At that time, all the large reflector telescopes were in the northern half of the world. But to study certain parts of space, like the center of the Milky Way and the Magellanic Clouds, you need to see the southern sky. So, they decided to build the observatory there.

At first, they thought about building the telescopes in South Africa. But tests showed that a place in the Andes mountains in Chile would be much better. So, ESO decided to build its observatory in Chile instead. The ESO Convention was signed on October 5, 1962, by Belgium, Germany, France, the Netherlands, and Sweden. Otto Heckmann became the first director of ESO. On November 15, 1963, Chile was officially chosen as the site for ESO's observatory.

Directors general of ESO (from left to right): Lodewijk Woltjer, Harry van der Laan, Catherine Cesarsky, Tim de Zeeuw and Xavier Barcons

In 1966, the first ESO telescope started working at the La Silla site in Chile. ESO also worked closely with CERN, another big European science group. In 1980, ESO's main offices moved to a new building in Garching, near Munich, Germany.

Countries That Are Members

Country	Joined
Belgium	1962
Germany	1962
France	1962
Netherlands	1964
Sweden	1964
Denmark	1967
Switzerland	1982
Italy	1982
Portugal	2001 January 1
United Kingdom	2002 July 8
Finland	2004 July 1
Spain	2006 July 1
Czech Republic	2007 January 1
Austria	2008 July 1
Poland	2014 October 28
Ireland	2018 September 28

ESO's Observatories in Chile

Even though ESO's main office is in Germany, its powerful telescopes are in northern Chile. This area is one of the best places in the southern hemisphere for looking at space. ESO runs three main observatories there:

• La Silla, home to the New Technology Telescope (NTT).
• Paranal, where the Very Large Telescope (VLT) is located.
• Llano de Chajnantor, where ALMA (the Atacama Large Millimeter/submillimeter Array) is located.

ESO is also building the Extremely Large Telescope (ELT). This will be the biggest visible and near-infrared telescope in the world. Construction started in June 2014 at a fourth site called Cerro Armazones.

Every year, scientists ask to use ESO telescopes about 2,000 times. This is much more than the time available! The discoveries made with these telescopes are published in many scientific papers each year. In 2017, over 1,000 papers used data from ESO.

ESO telescopes collect a huge amount of data. This information is stored in a special archive at ESO headquarters. The archive holds over 1.5 million images and other data. It totals about 65 terabytes, which is a massive amount of information!

La Silla Observatory

La Silla cluster of telescopes

La Silla is in the southern Atacama Desert, about 600 kilometers north of Santiago. It sits high up at 2,400 meters. This spot is very dark at night, far from city lights. It is one of the best places on Earth to see the stars. At La Silla, ESO uses three main telescopes: a 3.6-meter telescope, the New Technology Telescope (NTT), and the 2.2-meter Max-Planck-ESO Telescope.

Many discoveries have been made at La Silla. For example, the HARPS instrument found planets orbiting the star Gliese 581. One of these planets was the first rocky planet found in a "habitable zone" outside our solar system. This means it might be able to support life. La Silla telescopes also helped connect gamma-ray bursts (the most powerful explosions in the universe since the Big Bang) with exploding massive stars.

ESO 3.6-meter Telescope

The ESO 3.6 m Telescope

The ESO 3.6-meter telescope started working in 1977. It has been updated over the years. Now, it mainly uses the HARPS instrument to search for planets outside our solar system. It also studies how stars vibrate, which is called asteroseismology. This telescope is very good at measuring tiny changes in how stars move.

New Technology Telescope (NTT)

The New Technology Telescope

The New Technology Telescope (NTT) is a 3.58-meter telescope. It opened in 1989 and was the first in the world to have a main mirror controlled by a computer. This special mirror can change its shape during observations to keep images super clear. This technology, called active optics, was developed by ESO. Now, all big telescopes, including the VLT and the future ELT, use it.

The building that holds the NTT is also very clever. It is designed to let air flow smoothly around the mirror. This reduces air movement that can blur images, making them much sharper.

MPG/ESO 2.2-meter Telescope

The 2.2-meter telescope has been at La Silla since 1984. It is on loan to ESO from the Max Planck Society in Germany. ESO and the Max Planck Society share the time on this telescope. ESO is in charge of running and maintaining it.

This telescope has a special camera called WFI. It can take huge pictures of the sky, as big as the full moon! It has captured many amazing images of space objects. Another instrument, GROND, looks for the afterglow of gamma-ray bursts. These are the most powerful explosions in the universe.

Other Telescopes at La Silla

The Euler Telescope and the ESO 3.6-m Telescope (background) have discovered many exoplanets.

The Rapid Eye Mount telescope

La Silla also hosts several telescopes that are not run by ESO. These include the Swiss Euler Telescope and the Danish National Telescope.

• The Euler Telescope is a 1.2-meter telescope. It is used to find large planets outside our solar system. It also studies stars that change brightness and other space events.
• The 1.54-meter Danish National Telescope has been used at La Silla since 1979.

Dome of the Danish 1.54-metre telescope that has been in operation at La Silla Observatory since 1979

• The Rapid Eye Mount telescope (REM) is a small, fast telescope. It automatically follows up on gamma-ray bursts detected by satellites.
• The Belgian TRAPPIST telescope is 0.60 meters wide. It specializes in studying comets and exoplanets. It even helped show that the dwarf planet Eris might be smaller than Pluto.
• The Quick-action telescope for transient objects, TAROT, is a very fast robotic telescope. It can observe a gamma-ray burst right from the start.

Paranal Observatory

The Paranal Observatory is on top of Cerro Paranal mountain in the Atacama Desert. This mountain is 2,635 meters high. It is about 120 kilometers south of Antofagasta and 12 kilometers from the Pacific coast.

The observatory has seven major telescopes. These include the four 8.2-meter telescopes of the Very Large Telescope (VLT). There are also the 2.6-meter VLT Survey Telescope (VST) and the 4.1-meter Visible and Infrared Survey Telescope for Astronomy (VISTA). Plus, there are four smaller 1.8-meter telescopes that work together. In March 2008, parts of the James Bond film Quantum of Solace were filmed at Paranal.

A 360-degree panoramic view of the southern night sky from Paranal, with telescopes in foreground

Very Large Telescope (VLT)

Very Large Telescope (VLT). Complex of four large telescopes and several smaller ones.

VLT Laser Guide Star. The orange laser beam from the telescope is used for adaptive optics.

The main part of Paranal is the VLT. It has four almost identical 8.2-meter telescopes. Each one has two or three instruments. These big telescopes can also work together as one giant interferometer. This is called the ESO Very Large Telescope Interferometer (VLTI). It lets astronomers see details up to 25 times clearer than with just one telescope. The VLTI can see things with amazing detail, like being able to spot a car's headlights on the Moon!

The first VLT telescope started working in May 1998. The others followed in 1999 and 2000. Four smaller 1.8-meter telescopes were added between 2004 and 2007. They help with the VLTI when the main telescopes are busy.

Data from the VLT leads to many scientific papers being published every day. In 2017, over 600 papers used VLT data. Some of the VLT's discoveries include taking a picture of a planet outside our solar system. It also tracked individual stars moving around the supermassive black hole at the center of the Milky Way.

The four VLT telescopes were given names from the Mapuche language. These names are Antu (sun), Kueyen (moon), Melipal (Southern Cross), and Yepun (Evening Star).

Survey Telescopes at Paranal

Enclosure of British developed VISTA

VST seen in the back between VLT's dome-shaped auxiliary telescopes

The Visible and Infrared Survey Telescope for Astronomy (VISTA) is next to the VLT. VISTA's main mirror is 4.1 meters wide. It is very curved and built with amazing precision. VISTA was developed by universities in the United Kingdom. It started working in 2009 and takes high-quality images.

The VLT Survey Telescope (VST) is a 2.6-meter telescope. It has a 268-megapixel camera that can see an area of the sky four times larger than the full moon. The VST started working in 2011. It works with VISTA to survey the sky using visible light.

These survey telescopes help scientists study many things. They look at everything from the nature of dark energy to objects near Earth. VISTA and VST produce a huge amount of data. They collect more data every night than all the other VLT instruments combined.

Llano de Chajnantor Observatory

Three ALMA antennas on Chajnantor

ALMA antenna on route to Chajnantor plateau

The Llano de Chajnantor is a high plateau in the Atacama Desert. It is 5,100 meters high and very dry. This dry air is perfect for submillimetre astronomy. Water vapor in the air can block these light waves. So, a dry place is needed for this type of radio astronomy. The main telescopes here are:

• Atacama Pathfinder Experiment (APEX)
• Atacama Large Millimeter Array (ALMA)

ALMA is a telescope designed for millimetre and submillimetre astronomy. This type of astronomy explores a part of the universe we cannot see with normal light. It is great for studying the "cold universe." This includes huge, cold clouds in space where new stars are being born. These areas are often dark in visible light but shine brightly in millimetre and submillimetre light. This light also helps us study some of the earliest and most distant galaxies in the universe.

Atacama Pathfinder Experiment (APEX)

ESO hosts the Atacama Pathfinder Experiment, or APEX. ESO operates it for the Max Planck Institute for Radio Astronomy. APEX is a 12-meter telescope. It works with millimetre and submillimetre wavelengths, which are between infrared light and radio waves.

Atacama Large Millimeter/submillimeter Array (ALMA)

ALMA is a huge group of telescopes. It has 66 very precise antennas. They work together as one giant interferometer. The main group has 50 large 12-meter antennas. There is also a smaller group of four 12-meter and twelve 7-meter antennas. These antennas can be spread out across the desert over distances from 150 meters to 16 kilometers. This gives ALMA a "zoom" feature.

ALMA can explore the universe with amazing detail and sensitivity. Its vision is up to ten times sharper than the Hubble Space Telescope! ALMA is a huge project. Many countries from East Asia, Europe (ESO), North America, and Chile are working together on it.

ALMA's main goals include studying how stars, galaxies, and planets are born. It does this by observing gas and dust in space. It also studies distant galaxies and the leftover radiation from the Big Bang. ALMA started its first observations on October 3, 2011.

Learning About Space with ESO

Artist's impression of ESO Supernova Planetarium & Visitor Centre

ESO has a special department called ePOD. This group helps teach people about astronomy.

ePOD also runs the ESO Supernova Planetarium & Visitor Centre. This is an astronomy center located at ESO's headquarters in Garching, Germany. It opened on April 26, 2018. It is a great place for everyone to learn about space!

See also

In Spanish: Observatorio Europeo Austral para niños