European Southern Observatory


Courtesy ESO

 General Description

ESO (European Southern Observatory) is the pre-eminent intergovernmental organization in astronomy operating a number of the world's most powerful ground-based telescopes. The organisation employs around 680 staff members at its Garching, Munich headquarters and at sites in Chile. ESO is the world's most productive astronomical observatory. Scientific activity covers all topics of modern astronomy and is mostly the work of guest astrophysicists from the ESO member states. Because of the excellence of Swiss astronomy institutes, Swiss astronomers provide a very valuable contribution to ESO, among them the development of instruments for the discovery of exoplanets. ESO generates a large number of high-tech industry contracts. Some of the contracts relate to new optomechanical and optoelectronic systems for steering heavy equipment with extremely high accuracy. Others are for hardware and software for the operation of complex telescope instruments, mathematically advanced image analysis, and optimal retrieval, archiving and processing of extremely large amounts of data.


ESO owns four locations at high altitude in Northern Chile: La Silla, Paranal, Chajnantor and Cerro Armazones.

La Silla

La Silla (2’400m) is the original ESO site in Chile. It hosts 6 telescopes, among them the Swiss telescope Leonhard Euler (1.2m mirror).


Paranal (2’660m) hosts the Very Large Telescope VLT, an array of four identical telescopes with 8.2m mirrors. The telescope can see objects that are four billion times fainter than those seen with the naked eye. VLT will host the Espresso instrument, a new generation spectrograph, dedicated to two major scientific programmes: the search for rocky extra-solar planets in the habitable zone of their host stars, and the determination of the possible variability of physical constants. The instrument is built by the Espresso Consortium of Swiss (UNI GE), Italian, Portuguese, and Spanish institutes and will be delivered to ESO in exchange for Guaranteed Time of Observation (GTO). Espresso is expected to start operating in 2017.


Chajnantor (5’050m) on the high altitude Chilean plateau hosts ALMA (Atacama Large Millimeter-submillimeter Array), the world’s largest radio astronomy telescope. Inaugurated in 2013, the array of 66 12m and 7m diameter antennas is capable of observing the coldest celestial bodies of the universe.

Cerro Armazones

Cerro Armazones (3’060m) is the location for the European Extremely Large Telescope E-ELT. A new optical telescope (39m mirror) providing 15 times more light than VLT, E-ELT will address many of the unsolved questions in contemporary astronomy. The construction for E-ELT will last 10 years and first light is scheduled for 2025. The construction budget for E-ELT is 1’100 M€. 83% of this budget is allocated to industry contracts.

Founding year: 1962

Members (16): Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Italy, Netherlands, Poland, Portugal, Spain, Sweden, Switzerland, UK, Brasil (candidate)

Budget ESO 2021 : ~180 M€

Swiss financial contribution : ~4.9 %

Swiss involved research institutes : Uni BE, GE, LS, ZH, ETHZ

Procurement policy: Companies must be registered in the ESO global supplier data base. A quotation against a contract can only be made if the company is invited to do so by ESO. Contracts are awarded to the lowest priced technically and managerially compliant tender or, if specified, since 2019, according to a BVFM (Best Value for Money) evaluation procedure. For a multi-partner offer the ESO member state contribution must not be lower than 70% of the total contractual value.

Tenders below 150k€: ESO can choose to send requests for quotation to a limited supplier group, which means that only companies from some designated countries will be offered to bid. SMEs can explore the possibility of getting these smaller contracts that do not come out to public tender. This is ensured by close dialogue with the ILOs and/or ESO responsible.

  1. Tenders above 150K€: Tenders above 150k€ are published on the ESO procurement webpage. ESO uses a 3-step process.
  2. Request for Interest. ILOs are requested to suggest suitable national suppliers for the procurement. The reaction period for the ILOs is three weeks.
  3. Preliminary Inquiry. Pre-selection based on technical and financial information. The Preliminary Inquiry is open for 3 weeks.

Call for Tender. The response time after the Call for Tender is a minimum of 6 weeks.

Finance Committee must approve contracts exceeding 500 k€ and single-source procurements exceeding 250 k€.

ESO does not apply geo-return rules. Nevertheless a fair distribution of the contracts among ESO Member States is acknowledged. Yearly statistics on geographical return are available.

It is ESO's policy to require that at least 70% of the contract value is allocated to companies based in ESO member states and Chile.

Schweizerische Eidgenossenschaft
Confédération suisse
Confederazione Svizzera
Confederazium Svizra
Swiss Confederation


Federal Department of Ecomic Affairs,
Education and Research EAER
State Secretariat for Education,
Research and Innovation SERI
Uni Ge
swissmem logo
The Swiss Industry Liaison Office (ILO) is financed by the State Secretariat for Education Research and Innovation SERI. The Swiss ILO Convention signatory members supporting the ILO activity are EPFL, PSI, University of Geneva and SwissMEM.