Editing European Southern Observatory (section)

{{short description|Intergovernmental organization and observatory in Chile}}
{{Redirect|ESO|other uses|ESO (disambiguation)|the European Space Agency|ESA}}

{{EngvarB|date=July 2019}}

{{Dmy|date=February 2025}}

{{Infobox organization
| name         = European Organisation for Astronomical Research in the Southern Hemisphere
| image        = [[File:European Southern Observatory (ESO) logo.svg|145px]] [[File:ESO member states.svg|139px]]
| alt          = ESO's standard logo in blue color
| caption      = {{longitem|(L–R): ESO logo; Map of member states|style=width:300px; padding: 6px 0;}}
| abbreviation = ESO<ref>{{cite web |url=https://www.eso.org/public/about-eso/acronyms/ |title=ESO Glossary of Acronyms |access-date=2018-09-07 |archive-date=2013-09-11 |archive-url=https://web.archive.org/web/20130911024041/https://www.eso.org/public/about-eso/acronyms/ |url-status=live }}</ref>
| type         = [[Intergovernmental organisation]]
| purpose      = [[Astronomy]]
| headquarters = [[Garching]], Germany
| membership   = 16
| leader_title = Director General
| leader_name  = [[Xavier Barcons]]
| leader_title2 =
| leader_name2 =
| formation    = {{start date and age|1962}}
| language     = {{longitem|English, French, German}}
| website      = {{URL|https://www.eso.org/}}
}}

[[File:ESO Trailer.webm|thumb|Trailer of the European Southern Observatory]]

The '''European Organisation for Astronomical Research in the Southern Hemisphere''',<ref>{{cite web |url=https://www.eso.org/public/unitedkingdom/about-eso/organisation/ |title=ESO's Organisational Structure |access-date=2018-09-07 |archive-date=2018-09-07 |archive-url=https://web.archive.org/web/20180907182913/https://www.eso.org/public/unitedkingdom/about-eso/organisation/ |url-status=live }}</ref> commonly referred to as the '''European Southern Observatory''' ('''ESO'''), is an [[intergovernmental organization|intergovernmental research organisation]] made up of 16 member states for ground-based [[astronomy]]. Created in 1962, ESO has provided astronomers with state-of-the-art research facilities and access to the southern sky. The organisation employs over 750 staff members and receives annual member state contributions of approximately €162&nbsp;million.<ref>{{cite web |url=http://www.eso.org/public/about-eso/memberstates/ |title=Member States |date=2017-04-02 |access-date=2018-06-15 |archive-date=2020-06-15 |archive-url=https://web.archive.org/web/20200615083311/https://www.eso.org/public/about-eso/memberstates/ |url-status=live }}</ref> Its observatories are located in northern [[Chile]].

ESO has built and operated some of the largest and most technologically advanced [[telescope]]s. These include the 3.6 m [[New Technology Telescope]], an early pioneer in the use of [[active optics]], and the [[Very Large Telescope]] (VLT), which consists of four individual 8.2 m telescopes and four smaller auxiliary telescopes which can all work together or separately. The [[Atacama Large Millimeter Array]] observes the [[universe]] in the [[Terahertz radiation|millimetre and submillimetre]] wavelength ranges, and is the world's largest ground-based astronomy project to date. It was completed in March 2013 in an international collaboration by Europe (represented by ESO), North America, East Asia and Chile.<ref>{{cite web |url=http://www.almaobservatory.org/en |title=ALMA website |access-date=2011-09-21 |archive-date=2011-10-06 |archive-url=https://web.archive.org/web/20111006034647/http://www.almaobservatory.org/en |url-status=live }}</ref><ref>{{cite web |url=http://www.eso.org/sci/facilities/alma/ |title=Welcome to ALMA! |access-date=2011-05-25 |archive-date=2016-06-23 |archive-url=https://web.archive.org/web/20160623232705/http://www.eso.org/sci/facilities/alma/ |url-status=live }}</ref>

Currently under construction is the [[Extremely Large Telescope]]. It will use a 39.3-metre-diameter [[segmented mirror]], and become the [[List of largest optical reflecting telescopes|world's largest]] optical reflecting telescope when operational towards the end of this decade. Its light-gathering power will allow detailed studies of planets around other stars, the first objects in the universe, [[supermassive black hole]]s, and the nature and distribution of the [[dark matter]] and [[dark energy]] which dominate the universe.

ESO's observing facilities have made astronomical discoveries and produced several [[European Southern Observatory Catalog|astronomical catalogues]].<ref>{{cite web |url=http://archive.eso.org/starcat/astrocat/astrocat_screen_list.html |title=ESO Archive |access-date=2011-04-28 |archive-date=2011-07-26 |archive-url=https://web.archive.org/web/20110726144715/http://archive.eso.org/starcat/astrocat/astrocat_screen_list.html |url-status=dead }}</ref> Its findings include the discovery of the most distant [[gamma-ray burst]] and evidence for a [[black hole]] at the centre of the [[Milky Way]].<ref>{{cite journal| title = A gamma-ray burst at a redshift of 8.2| volume=461 | issue = 7268| doi = 10.1038/nature08459 | pmid = 19865165| journal=Nature | pages=1254–1257|arxiv = 0906.1577 |bibcode = 2009Natur.461.1254T | year = 2009| last1 = Tanvir| first1 = N. R.| last2 = Fox| first2 = D. B.| last3 = Levan| first3 = A. J.| last4 = Berger| first4 = E.| last5 = Wiersema| first5 = K.| last6 = Fynbo| first6 = J. P. U.| last7 = Cucchiara| first7 = A.| last8 = Krühler| first8 = T.| last9 = Gehrels| first9 = N.| last10 = Bloom| first10 = J. S.| last11 = Greiner| first11 = J.| last12 = Evans| first12 = P. A.| last13 = Rol| first13 = E.| last14 = Olivares| first14 = F.| last15 = Hjorth| first15 = J.| last16 = Jakobsson| first16 = P.| last17 = Farihi| first17 = J.| last18 = Willingale| first18 = R.| last19 = Starling| first19 = R. L. C.| last20 = Cenko| first20 = S. B.| last21 = Perley| first21 = D.| last22 = Maund| first22 = J. R.| last23 = Duke| first23 = J.| last24 = Wijers| first24 = R. A. M. J.| last25 = Adamson| first25 = A. J.| last26 = Allan| first26 = A.| last27 = Bremer| first27 = M. N.| last28 = Burrows| first28 = D. N.| last29 = Castro-Tirado| first29 = A. J.| last30 = Cavanagh| first30 = B.| display-authors= 29| hdl = 10261/18184| s2cid=205218350 }}</ref><ref>{{cite journal| title = Monitoring stellar orbits around the Massive Black Hole in the Galactic Center| year = 2009| last1 = Gillessen| first1 = S.| display-authors = 4| last2 = Eisenhauer| first2 = F.| last3 = Trippe| first3 = S.| last4 = Alexander| first4 = T.| last5 = Genzel| first5 = R.| last6 = Martins| first6 = F.| last7 = Ott| first7 = T.| doi = 10.1088/0004-637X/692/2/1075| journal = [[The Astrophysical Journal]]| volume = 692| issue = 2| pages = 1075–1109|arxiv=0810.4674|bibcode = 2009ApJ...692.1075G | s2cid = 1431308}}</ref> In 2004, the VLT allowed astronomers to obtain the first picture of an [[extrasolar planet]] ([[2M1207b]]) orbiting a [[brown dwarf]] 173 light-years away.<ref>{{cite journal| title = A giant planet candidate near a young brown dwarf. Direct VLT/NACO observations using IR wavefront sensing|bibcode=2004A&A...425L..29C| last1 = Chauvin| first1 = G.| display-authors = 4| last2 = Lagrange| first2 = A.-M.| last3 = Dumas| first3 = C.| last4 = Zuckerman| first4 = B.| last5 = Mouillet| first5 = D.| last6 = Song| first6 = I.| last7 = Beuzit| first7 = J.-L.| last8 = Lowrance| first8 = P.| volume = 425| date = 2004| pages = L29| journal = [[Astronomy and Astrophysics]]| doi = 10.1051/0004-6361:200400056| issue = 2|arxiv = astro-ph/0409323 |s2cid=15948759}}</ref> The High Accuracy Radial Velocity Planet Searcher ([[HARPS]]) instrument installed on the older ESO 3.6 m telescope led to the discovery of extrasolar planets, including [[Gliese 581c]]—one of the smallest planets seen outside the [[Solar System]].<ref>{{cite web| url = http://obswww.unige.ch/Instruments/harps/| title = The HARPS Home page| access-date = 2011-09-21| archive-date = 2019-03-23| archive-url = https://web.archive.org/web/20190323213158/http://obswww.unige.ch/Instruments/HARPS/| url-status = dead}}</ref>