The Organisation Reaching New Heights in Astronomy — ESO Long Term Perspectives Tim de Zeeuw1 in science, are of enormous interest to costs and place the main contracts. the general public, and are instrumental Phase A design studies for ESO’s OWL in stimulating young people to consider concept and the competing EURO50 1 ESO a career in science or engineering, which concept for extremely large optical- is important for our society. infrared telescopes were under develop- ment. Other giant telescope projects A comprehensive description of ESO The construction of a major astronomical were gaining momentum elsewhere in the in the current global astronomical con- facility typically takes a decade or longer. world. The ESO Council realised the need text, and its plans for the next decade ESO has built three such observatories to develop a policy for the near future, and beyond, are presented. This survey (on La Silla, Paranal and Chajnantor in which led to the Resolution on Scientific covers all aspects of the Organisation, Chile) since its founding in 1962 and is Strategy. The Resolution is included in full including the optical-infrared pro- now constructing the European Extremely in the Appendix. gramme at the La Silla Paranal Obser- Large Telescope (ELT) on Armazones vatory, the submillimetre facilities ALMA near Paranal. They take advantage of At the time of writing, twelve years later, and APEX, the construction of the developments in technology and in turn ESO’s programme at visual/infrared 39-metre European Extremely Large stimulate further technology development. wavelengths has Paranal as its flagship, Telescope and the science operation ESO’s observatories make key contribu- and the well-instrumented system com- of these facilities. An extension of the tions to all aspects of astrophysics and prising the VLT and VLTI, supplemented current optical/infrared/submillimetre are the main ground-based observational by VISTA and VST, is world-leading. facilities into multi-messenger astron- resource for astronomers in most of the Following extensive design studies, the omy has been made with the decision Member States. 39-metre ELT is under construction on to host the southern Cherenkov Tele- Armazones, as an integral part of the scope Array at Paranal. The structure Paranal system, and is on track for first of the Organisation is presented and 1.1 The 2004 Council Resolution on light in 2024. It has a good chance of the further development of the staff is Scientific Strategy being the first of the next generation of described within the scope of the long- giant telescopes to go into operation. range financial planning. The role of ESO’s current programme is guided by The venerable 3.6-metre telescope and Chile is highlighted and expansion of the the Council Resolution on Scientific the New Technology Telescope (NTT) number of Member States beyond the Strategy, which was formulated in 2004 on La Silla continue to produce excellent current 15 is discussed. The strengths when ESO had 11 Member States. science. In the submillimetre regime, the of the ESO model, together with chal- The Very Large Telescope (VLT) had Atacama Pathfinder Experiment (APEX) lenges as well as possible new opportu- entered full operations with all four Unit came on line in 2006 and the ALMA Part- nities and initiatives, are examined Telescopes (UTs), but not all of the first- nership has completed the construction and a strategy for the future of ESO is generation instruments had been com- of the transformational array which is now outlined. pleted. An additional instrument, the operational on Chajnantor. In addition, High Acuity Wide field K-band Imager ESO will host the Cherenkov Telescope (HAWK-I), was in development, and four Array (CTA) South in the Paranal area, 1. Introduction second-generation instruments had and will operate it for the CTA Partnership been selected (X-shooter, the K-band on a cost-reimbursement basis. Astronomy is one of the oldest sciences Multi Object Spectrograph [KMOS], the and can be defined as the study of the Spectro-Polarimetric High-contrast Exo- ESO’s internal organisation has been Universe and everything in it. Advances planet REsearch instrument [SPHERE] adapted to carry out this challenging in technology during the past half-century and the Multi Unit Spectroscopic Explorer portfolio of major programmes. Many have made it possible to build increas- [MUSE]). The VLT Interferometer (VLTI) internal processes have been stream- ingly powerful facilities on the ground and was operational with the two-beam mid- lined and harmonised. Since early 2014 in space to study the Universe across infrared instrument MIDI. The VLT Survey all staff at Headquarters work in a single the entire electromagnetic spectrum and Telescope (VST) was under construction set of interconnected buildings on the to detect particles and gravitational waves but had experienced delays. The Visible ESO premises and are no longer spread from celestial sources. This has resulted and Infrared Survey Telescope for Astron- over multiple buildings on the Garching in tremendous advances, including: the omy (VISTA) had been agreed under the research campus. A world-leading out- discovery of the mysterious dark energy; UK accession to ESO, and construction reach and education centre, the ESO probing the extreme physics of black had started. ESO was operating three Supernova Planetarium & Visitor Centre, holes, supernovae and gamma-ray bursts; telescopes on La Silla and hosted a num- donated by the Klaus Tschira Foundation, understanding the formation and evolu- ber of independent telescope projects will be inaugurated in 2018. tion of stars and galaxies; and the direct there. The Atacama Large Millimeter/sub- detection and study of planets around millimeter Array (ALMA) was under con- In this same period, the accession of other stars, which may have the potential struction by the partnership between Spain (2006), the Czech Republic (2007), to harbour life. These discoveries address East Asia, ESO and North America, but Austria (2009) and Poland (2015) some of the most fundamental questions re-baselining was required to contain increased the number of ESO Member 2 The Messenger 166 – December 2016 States to 15. The Brazilian accession agreement, signed in December 2010, )/ESO was ratified by the Brazilian Congress and Senate in 2015, but still awaits the final signature by the President. Formal and informal discussions with a number atacamaphoto.com of other countries regarding membership are ongoing. The entire programme is under significant financial pressure caused by factors beyond ESO’s control. These include rap- idly increasing costs for labour in Chile, J. L. Dauvergne & G. Hüdepohl ( unfavourable exchange rates and special organisational contributions to the CERN Pension Fund. 1.2 Global context State-of-the-art fully steerable optical/ infrared telescopes with primary mirrors will provide very accurate positions and Figure 1. Aerial view of the Paranal Observatory. 8 metres, or larger, in diameter are opera- motions for more than a billion stars in tional at various locations around the the Milky Way by 2020. ESA’s Euclid construction into two phases. The first world, supported by different organisa- mission expects to provide an infrared phase comprises 90 % of the project. tions or partnerships. The main centre in map of the entire extragalactic sky by It has been authorised, is independent the northern hemisphere is Mauna Kea, the middle of the next decade. The Large of the timing of the completion of the which hosts the two Keck telescopes, the Synoptic Survey Telescope (LSST) on Brazilian accession, and was enabled by Subaru telescope and the Gemini North Cerro Pachón will start mapping the entire the accession of Poland. A significant telescope. The Large Binocular Tele- accessible sky twice per week in 2023, uncertainty in the planning for the future scope on Mount Graham and the Gran sensitive to new transient phenomena. was removed in June 2016 when Council Telescopio Canarias on La Palma provide At that time, the northern and southern gave approval to place the Phase 1 ELT northern access to astronomers from components of the Cherenkov Telescope contracts in accordance with first light in (some of) the ESO Member States. The Array (CTA), designed to detect optical 2024, even if this might require making Gemini South telescope on Pachón in flashes in the atmosphere caused by high- use of the credit facility in place with the Chile and the VLT on Paranal cover the energy gamma-rays from the Universe, European Investment Bank. It is therefore southern hemisphere. Two independent should be operational as well. Ground- timely to present ESO’s Long Term Per- international partnerships aim to build based facilities in the design phase, or spectives, setting out the planned devel- the 25-metre Giant Magellan Telescope on the drawing board, include the Square opment of ESO’s programme over the (GMT) on Las Campanas in Chile and the Kilometre Array, to be built in stages in next fifteen years, and including the Thirty Meter Telescope (TMT). The latter South Africa and Australia, a large single organisational perspective, financial plan- was initially planned to be on Mauna Kea, submillimetre dish on Chajnantor, a large ning and risks, options for funding of but the location is presently in doubt. In wide-field telescope for highly multiplexed ELT Phase 2, opportunities beyond the the submillimetre radio regime ALMA has spectroscopic surveys, new facilities to baseline programme over a longer period, no competition (thanks to its sensitivity, measure cosmic rays and a world-wide and an assessment of the ESO model. baseline range, size and global character), network of gravitational wave detectors except for the upgraded Plateau de Bure with sufficient angular resolution to allow NOrthern Extended Millimeter Array electromagnetic telescopes to locate and 2. Optical-infrared programmes (NOEMA), which can access the entire characterise the sources.