ESO Announcements

President of the Czech Republic and Chilean Minister of Foreign Affairs visit ESO’s Paranal Observatory in Chile

Mon, 20 Apr 2026 16:00:00 +0200

Petr Pavel, President of the Czech Republic, his wife Eva Pavlová, Francisco Pérez Mackenna, Chilean Minister of Foreign Affairs, and a large Czech delegation have concluded a visit to ESO’s Paranal Observatory in Northern Chile. The delegation included the Czech Ambassador to Chile, Pavel Bechny, the President of the Czech Academy of Sciences, Radomír Pánek, the President of the Astronomical Institute of the Czech Academy of Sciences, Michal Bursa, as well as journalists and representatives of Czech companies.

ESO’s Director General Xavier Barcons welcomed President Pavel, Minister Pérez Mackenna and the rest of the delegation to the Paranal Observatory on 17 April. The visitors toured ESO's Extremely Large Telescope (ELT) construction site, before heading to the Very Large Telescope (VLT), where they observed the opening of one of the telescopes. Later in the evening, they watched the lasers from the VLT platform — a key element of the telescope’s adaptive optics system that compensates for turbulence in the Earth’s atmosphere — and visited the VLT control room. During their stay, the high-level visitors had the opportunity to experience Paranal's facilities and outstanding dark skies in person, as well as find out more about the ELT and how it will expand our understanding of the Universe. The delegation also learned about the business opportunities created by ESO's development of cutting-edge technology..

The Czech Republic, joined ESO in 2007, becoming the first Member State from the Central and Eastern European region. Czech institutions have made important contributions to the development of instruments and telescopes owned by ESO and those hosted at ESO sites. For instance, Czech companies have contributed to both Paranal and ELT instrumentation. Further south, at ESO’s La Silla Observatory, a consortium led by the Czech Academy of Sciences has also given new life to ESO’s 1.52m telescope, with the PLATO Spec instrument.

"We are very pleased to welcome President Pavel and his delegation to Paranal,” said Barcons. “The Czech Republic has been a very engaged and supportive ESO Member State for almost 20 years. The introduction of an engineering and scientific trainee programme at ESO for Czech nationals, now a model for other Member States, and the engagement of Czech institutes in ELT instrumentation, are examples of how the collaboration between ESO and the Czech Republic is both advancing astronomy and investing in the next generation of scientists and engineers."

Regarding the presence of Minister Pérez Mackenna during the visit, Barcons said: "The Chilean Minister of Foreign Affairs' participation on this visit underscores the solid and fruitful relationship that ESO has maintained with Chile — which hosts all of our existing telescopes — for more than six decades. Technology developed by the Czech Republic and other ESO Member States bears scientific fruits in large part thanks to this long-standing collaboration with Chile, whose remarkably dark and pristine skies we are privileged to observe from ensure the highest scientific value of the observations."

Puerto de Ideas Antofagasta 2026: second night tour at Paranal Observatory will take place on 25 April

Fri, 10 Apr 2026 17:00:00 +0200

Following a successful first edition, the European Southern Observatory (ESO) will hold its second public night tour of ESO’s Paranal Observatory in northern Chile. The tour is taking place in the context of ESO’s participation in the Puerto de Ideas Antofagasta 2026 Science Festival, happening in the nearby city of Antofagasta. This tour will take place on Saturday 25April.: Registration is free, and spots are limited and assigned on a first-come, first-served basis.

Key Information:

Where: Paranal Observatory

When: Saturday, 25 April.

Time: Bus departs from Antofagasta at 14:30 and leaves Paranal Observatory at 19:50, when the tour ends.

Registration: Free and open to the public on a first-come, first-served basis.
- Registration opens on April 16 via the Puerto de Ideas website.

Capacity: 40. Limited spots available, on a first-come, first-served basis.

What does the visit include?
- Round-trip bus transportation from a pickup point in the city of Antofagasta, which will be communicated to confirmed visitors.
- The tour at the observatory will last three hours, during which visitors will be able to see the opening of ESO’s Very Large Telescope (VLT), watch the sunset from the Cerro Paranal platform, and visit the control room where the telescopes are operated. Additionally, depending on operational conditions, the tour will include access to one of the VLT Unit Telescopes (UT) and the Paranal Residencia.
- At the end of the tour, there will be a guided naked-eye sky observation during which visitors can appreciate the beauty of the world’s clearest skies and become familiar with some of the celestial objects visible at this time of the year.

Can I get there on my own?
- No. ESO provides round-trip transportation from the pickup point in the city of Antofagasta only for confirmed visitors. It is not permitted to arrive at the observatory by your own means.

When is the next night tour?
- Unlike regular Saturday tours, these night tours are held only on select dates throughout the year, generally in conjunction with special regional or national events. Each new date will be announced on this website and on ESO Chile’s Instagram: @eso.chile .

ESO launches first programme of night tours of scientific observatories in Chile

Fri, 13 Mar 2026 18:00:00 +0100

In March 2026, on the occasion of Chile’s Astronomy Day celebrations, ESO will mark a milestone by launching its first programme of public night tours at its La Silla and Paranal observatories. These visits will give people from Chile and around the world the opportunity to see some of the Organisation's most iconic telescopes, as well as enjoy the planet's most pristine dark skies. TICKETS ARE SOLD OUT FOR THE MARCH 21ST TOUR.

The programme will offer at least eight visits per year, during which the public will see the opening of telescopes at sunset in La Silla or Paranal and observe the stars, with the naked eye, under one of the darkest skies in the world. The programme will also include guided tours of different areas of the observatories, round-trip transportation from different cities in the Antofagasta and Coquimbo regions, as well as some surprises.

The first visit will take place at the Paranal Observatory on March 21 as part of the celebrations for Astronomy Day in Chile. It will also have the collaboration of the Antofagasta Region office of Chile’s National Tourism Service (SERNATUR). The rest of the night tours at Paranal and La Silla will be scheduled annually to coincide with emblematic dates, including the Puerto de Ideas Antofagasta festival, Chile’s National Heritage Day, Chilean Science Week, among others.

For this inaugural tour, registration will be through SERNATUR Antofagasta's social media channels and will be open to anyone in the region, including domestic and international tourists. For future visits, registration details will be provided through ESO's official channels.

These new night tours will last three hours at the observatories, where visitors will be able to watch the sunset from the observatories and visit the control rooms from where the telescopes operate. In addition, depending on operational conditions, the visits will allow visitors to see areas of ESO’s telescopes such as the Very Large Telescope (VLT) at Paranal or the New Technology Telescope (NTT) at La Silla.

Each visit will also include a guided observation of the sky with the naked eye, during which visitors will be able to appreciate the beauty of the world's most pristine skies and familiarise themselves with some of the celestial objects visible at different times of the year.

For decades, ESO has offered a regular programme of public visits that attracts more than 7,000 people a year and that, until now, only included daytime tours. Regarding this, Laura Ventura, ESO's Deputy Representative in Chile, said: “We are proud to be able to enrich the programme of visits to our observatories, so that more people, particularly from the respective regions and communities, can learn about this scientific, technological, and natural heritage that is unique in the world. It is a dream of many years that is now coming true.”

Italian Minister of University and Research visits ELT site

Fri, 13 Mar 2026 14:00:00 +0100

Anna Maria Bernini, the Italian Minister of University and Research, and a small delegation have completed a visit to ESO’s Extremely Large Telescope (ELT) in Chile’s Atacama Desert. The group included Valeria Biagiotti, Italy’s Ambassador to Chile, and Roberto Ragazzoni, President of the Italian National Institute for Astrophysics (INAF) and ESO Council Member. During the visit, the Minister and her delegation learnt about ESO’s groundbreaking facilities and saw first-hand the progress at Cerro Armazones, where the ELT is being constructed.

On 12 March, ESO’s Director General Xavier Barcons and ELT Programme Manager Roberto Tamai welcomed Minister Bernini — who travelled to Chile for the inauguration of the country’s new President — and briefed the visitors on ESO’s mission and operations. The delegation then toured the ELT site, learning about the 'world’s biggest eye on the sky' and Italy's substantial contributions to the project. Later, they visited the future southern-hemisphere site of the Cherenkov Telescope Array Observatory, located just a few kilometres from the ELT.

Italy, an ESO Member State since 1982, has played a pivotal role in many of the organisation's technological and scientific achievements. For example, several current and future instruments operating on ESO telescopes were built by consortia led by INAF institutes. Italy also maintains a leading role in the ELT: a consortium of Italian companies is currently constructing the dome and telescope structure, representing the largest ground-based astronomy contract ever awarded. The direct economic return to Italian companies and institutions participating in ESO projects exceeded 360 million EUR over the 2008-2025 period.

More than 1100 studies with ESO data published in 2025

Tue, 10 Mar 2026 14:00:00 +0100

Around 1150 studies using data collected at ESO's observatories were published last year — the second year in a row that publications have exceeded 1100. It also marks the ninth consecutive year where observations at ESO's facilities have led to more than 1000 published studies annually. The ESO Library, Documentation, and Information Services Department have updated their publication statistics to include 2025 with a detailed breakdown of the contributions from each ESO facility [1].

As in previous years, data from ESO's Very Large Telescope (VLT) and the VLT interferometer (VLTI) have dominated in publications, contributing to around 670 studies in 2025. The facilities' broad range of instruments, plus the location at Paranal Observatory in Chile's Atacama Desert — a site with unique observing conditions including pristine dark skies — make them a flagship in ground-based astronomy. The Multi Unit Spectroscopic Explorer (MUSE) continues its six-year streak as the most productive VLT/I instrument, with data in over 200 papers. A highlight from MUSE last year was the publication of an ultra-detailed thousand-colour image of the Sculptor Galaxy. Another highlight from the VLT published last year used data from the Ultraviolet and Visual Echelle Spectrograph (UVES), the second most productive VLT instrument with over 120 papers in 2025, to find a planet in a perpendicular orbit to a pair of stars.

The survey facilities, ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA) and the VLT Survey Telescope (VST) [2], also found at Paranal Observatory, produced data for over 100 papers. Data from ESO's first observatory, La Silla, contributed to about 200 studies last year, an increase from 177 in 2024. This shows how the observatory remains at the forefront of research, especially thanks to instruments such as HARPS, High Accuracy Radial velocity Planet Searcher, on ESO's 3.6-metre telescope.

The Atacama Large Millimeter/Submillimeter Array (ALMA), co-owned by ESO, provided data for over 550 publications in 2025. Around half of these papers relied on observing time granted to astronomers based in Europe. Highlights of ALMA studies published last year include the discovery of oxygen in the most distant known galaxy and observations of the creation of a new solar system. Located next to ALMA, observations from the Atacama Pathfinder Experiment (APEX), which was operated and hosted by ESO until the end of 2025, led to around 45 papers last year. Of these, close to 20 used data obtained during ESO observing time.

A record number of publications employed data from the ESO Science Archive Facility, with around 530 papers relying partly or exclusively on archival data. This also made 2025 the year with the highest percentage of ESO publications using the archive, at 46%, underscoring the value of legacy observations in cutting-edge astronomical research. Furthermore, over a quarter of all 2025 publications relied on archival data alone, without any ESO observations obtained by the authors themselves.

The impressive publication numbers emphasise the significant role ESO plays in helping astronomers advance our understanding of the Universe. This is made possible thanks to the work of the wider astronomical community and ESO staff, the advanced technology of ESO’s facilities, and the continued support of ESO’s member states and of Chile.

Notes

[1] Papers can use data from more than one facility, therefore the total number cannot be calculated by adding all publications of the individual sites.

[2] The VST project was a joint venture between ESO and the Capodimonte Astronomical Observatory, part of the Italian National Institute for Astrophysics (INAF). As of 1 October 2022, this is a sole project of INAF, hosted by ESO at Paranal. Only papers based (entirely or partly) on ESO VST time are included in the statistics.

More Information

The statistics presented here are derived from the ESO Telescope Bibliography (telbib), a database of refereed papers published by the ESO users community. Telbib is developed and curated by the ESO Library, Documentation, and Information Services Department. While text-mining scripts are applied when screening the literature for ESO data papers, articles are carefully examined by the curators before they are added to the database to ensure that all telbib papers use partly or exclusively data from ESO facilities for which observing time was recommended by ESO. The public telbib interface provides visualisations of search results including on-the-fly graphs and predefined charts.

German Federal Minister of Research, Technology and Space, German dignitaries visit ESO’s Paranal Observatory

Fri, 06 Feb 2026 12:00:00 +0100

Dorothee Bär, Federal Minister of Research, Technology and Space of Germany, Markus Blume, Bavarian State Minister for Science and the Arts, Thomas Reiter, Director General ‘Space and Security’, Federal Ministry of Research, Technology and Space of Germany, and a high-profile delegation — including Patrick Cramer, President of the Max Planck Society — have completed a visit to ESO’s Paranal Observatory in Northern Chile, home to some of the most advanced ground-based telescopes in the world. The visit provided an excellent opportunity for the Ministers and the delegation to experience Paranal, its facilities and its stunning dark skies in person, following a visit to ESO Headquarters and the ESO Supernova Planetarium and Visitor Centre last year.

On 4 February, ESO’s Director General Xavier Barcons together with Andreas Kaufer, ESO’s Director of Operations and Director General designate, welcomed Federal Minister Bär, State Minister Blume and the rest of the delegation to the Paranal Observatory. The guests visited the ELT Technical Facility, a maintenance and assembly site for components of ESO’s Extremely Large Telescope (ELT), before heading to the Very Large Telescope (VLT). The next day, they toured the ELT site, on nearby Cerro Armazones, where they saw the progress on the upcoming ‘world’s biggest eye on the sky’. During the two-day visit, the high-level visitors experienced the pristine and fragile dark skies at Paranal, got a first-hand impression of ESO’s operations in Chile, saw technology and engineering development done in Germany and elsewhere in Europe in action at the observatory, and learnt about the ELT’s potential to revolutionise our understanding of the Universe.

Germany has played a major role in many of ESO’s technological and scientific achievements, producing mirror blanks for the VLT, as well as the ELT, while several German research centres (including Max Planck Society institutes and the Leibniz Institute for Astrophysics Potsdam) have led consortia designing and building instruments for ESO’s telescopes. In her address, Minister Bär emphasised the need to protect the natural heritage, such as the dark and quiet skies, as they inspire the younger generations in their curiosity for STEM research. She highlighted the importance of ground-based astronomy, its synergies with space research and the significance of developing and investing in both fields, as they drive technology in Germany and the whole of Europe.

BlueMUSE: ESO signs agreement for new instrument on the VLT

Fri, 30 Jan 2026 16:00:00 +0100

Today, ESO has signed the agreement for the construction of the Blue Multi Unit Spectroscopic Explorer (BlueMUSE), an upcoming instrument for ESO’s Very Large Telescope (VLT). The signing marks a major first step in the development of BlueMUSE , which will offer new and unique science opportunities to astronomers. Its evolved technology will enable detailed observations within our galaxy, helping study targets as varied as massive stars, nebulae and comets. It will also revolutionise the study of the distant Universe by allowing the detection of the diffuse material in the space between galaxies and helping us understand how matter moves within it.

Earlier today, ESO’s Director General Xavier Barcons and Céline Reylé, the Deputy Director for Science for Astronomy and Astrophysics at the French National Centre for Scientific Research (CNRS), signed the BlueMUSE agreement at the ESO Headquarters in Garching, Germany. The CNRS’s Centre de Recherche Astrophysique de Lyon (CRAL – CNRS/ENS de Lyon/Claude Bernard Lyon 1 University) is the institution leading the instrument consortium, which consists of multiple institutes from Europe and Australia. Also in attendance were the French Science and Higher Education Attaché for Southern Germany, Emmanuel Delille, the Principal Investigator of BlueMUSE Johan Richard and the Project Manager Rémi Giroud, both from CRAL, in addition to other dignitaries of ESO and the BlueMUSE consortium [1], to commemorate the next step in the instrument’s construction.

Based on the successful technology of the MUSE instrument installed at the VLT, BlueMUSE is an integral-field spectrograph. It is designed to not only capture a 2D image of a target (or multiple targets) but also split the light into its component colours or wavelengths at each pixel, resulting in a full 3D dataset with comprehensive information on the target object. As MUSE has become one of the most productive and requested ESO instruments, the astronomical community has been hoping for a similar instrument for some time — this is now becoming a reality.

While like MUSE in many respects, BlueMUSE will observe in shorter and therefore bluer wavelengths, with higher spectral resolution (how finely it can distinguish between different wavelengths). This means it will strongly complement large ground- and space-based facilities, such as ESO’s upcoming Extremely Large Telescope and the James Webb Space Telescope, which are optimised to observe in the infrared.

Anticipated to see first-light in 2034, BlueMUSE will enable new science opportunities, beyond those possible with MUSE. It will survey larger samples of massive stars in the Milky Way and its galactic neighbourhood, helping answer key questions about stellar evolution. Further afield, it will be able to observe faint galaxies, as well as starburst galaxies, probing their extreme star-forming environment. BlueMUSE will also be ideally suited to study the distant Universe, in particular to detect the very diffuse, elusive matter that permeates the space between galaxies, as well as to probe the emergence of the first galaxy clusters.

Notes

[1] Attendees at the signing ceremony included Karine Perraut (French ESO Council delegate, from the Institut national des sciences de l’Univers (INSU), CNRS Earth & Space, France), Florence Laurent (BlueMUSE System Engineer at CNRS), Davor Krajnović (BlueMUSE Project Scientist, Leibniz-Institut für Astrophysik Potsdam, Germany), Alexandre Jeanneau (BlueMUSE Lead Optical Engineer at CNRS).

From ESO, in addition to Xavier Barcons, Frédéric Derie (Project Manager), Francesco Belfiore (Project Scientist), Reinhold Dorn (Project Engineer), Michele Cirasuolo (Instrumentation Programme Manager), Suzanne Ramsay (Deputy Instrumentation Programme Manager), Céline Péroux (Programme Scientist), Andrea Capardi (Programme Controller), Enrico Marchetti (Instrumentation Programme Engineer), Emanuela Ciattaglia (Instrumentation Programme Engineer), Diogo Rio Fernandes (Instrumentation Programme Engineer), Alain Delorme (Acting Head of Contracts & Procurement) and Cyrielle Blanc (Contract and Procurement Officer) were present.

More Information

The BlueMUSE project will be built by an international consortium composed of 9 research institutes in multiple countries and ESO. The consortium consists of

Australia: Australian Astronomical Optics; Macquarie University
France: Centre de Recherche Astrophysique de Lyon (CRAL - CNRS/ENS de Lyon/Claude Bernard Lyon 1 University; lead); Astrophysique, Instrumentation & Modélisation (AIM – CEA/CNRS/ Université Paris Cité); Institut de Recherche sur les lois Fondamentales de l’Univers (CEA/Saclay)
Germany: Leibniz Institute for Astrophysics Potsdam (AIP) in association with University of Potsdam and University of Göttingen
Portugal: Institute of Astrophysics and Space Sciences
Sweden: Department of Astronomy, Stockholm University
Switzerland: Observatoire astronomique de l’Université de Genève; Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL)
United Kingdom: Centre for Advanced Instrumentation and Centre for Extragalactic Astronomy, Physics Department, Durham University

ESO also contributes to the project development.

Winners announced for the ESO–Chile 2025 Joint Committee

Tue, 13 Jan 2026 14:00:00 +0100

The ESO–Government of Chile Joint Committee has announced 16 winning projects from the 2025 call, which will distribute more than 600 million Chilean pesos in initiatives dedicated to supporting astronomy dissemination and education projects in Chile, and supporting astronomy post-doctoral programmes in Chilean institutions.

This year 98 eligible proposals were received. Almost 44% of the applications funded were proposals for the dissemination and education on astronomy, while 38% fall on supporting astronomical post-doctoral programmes and technology development projects in Chilean institutions.

“This fund has been an instrumental tool for the development of astronomy in Chile, not only for supporting academic positions in Chilean universities and technological development related to astronomy, but also for its dissemination. In the next years this will be a very important area for the Chilean community, with the upcoming celebration of the International Astronomical Union (IAU) General Assembly in 2030 in Chile,” said Itziar de Gregorio Monsalvo, ESO representative in Chile, after the results were delivered.

Since 1996, the ESO–Government of Chile Joint Committee has been one of the main funds for the development of the area as it supports postdoctoral programmes and academic positions in astronomy in Chilean institutions. In addition, it finances national and foreign scientific visits, technology demonstrators, and educational programs for teaching and disseminating this science in the country.

The Joint Committee of ESO–Government of Chile is made up of representatives of ESO and the Government of Chile through the Directorate of Energy, Science and Technology and Innovation of the Ministry of Foreign Affairs, the Ministry of Science, Technology, Knowledge and Innovation and the Chilean Astronomy Society.

The winning projects of the ESO-Government of Chile 2025 Joint Committee are:

#	Institution / Institución	Responsible person / Persona responsible	Name of the project / Nombre del proyecto	Type / Tipo	Funds in pesos / Fondos en pesos
1	Sociedad Chilena de Astronomía	Daniela Olave	Chilean Representation to the Astronomy & Astrophysics (A&A) journal	6	5.000.000
2	Sociedad Chilena de Astronomía	Mayte Alfaro Cuello	‘Beca Adelina Gutiérrez’: SOCHIAS Student Travel Grant for Conferences and Short Research Visits	6	10.000.000
3	Universidad Técnica Federico Santa María	Odette Toloza	Colaboración USM-Warwick: Consolidación de la USM como referente chileno en investigación de enanas blancas en la era de 4MOST y SDSS-V	5	8.910.000
4	Universidad Técnica Federico Santa María	Rory Smith	Bringing the Immersive Universe to remote Communities: Year 1	3	19.999.000
5	Universidad de Chile	Walter Max-Moerbeck	Unveiling Cosmic Magnetism and the Origin of Cosmic Rays in the CTAO Era	1	68.500.000
6	Universidad de Concepción	Rodrigo Herrera Camus	Our Sky, Our Future: Chilean Voices on the Extremely Large Telescope	3	20.000.000
7	Universidad de Santiago	Carla Hernández Silva	Agentes Inmobiliarios Intergalácticos: Llevando la Astrobiología a la sala de clases por medio de un juego de mesa	3	11.000.000
8	Pontificia Universidad Católica de Chile	Manuela Zoccali	Laboratorio de Astrofísica Solar Escolar	3	13.000.000
9	Universidad Diego Portales	Lucas Cieza	Enabling the (sub)mm capabilities of the UDP Cosmic Dust Laboratory	4	142.900.000
10	Universidad de Concepción	Neil Nagar	Insights into Jets and Black Hole Demographics by imaging from 50–1000s Rg	1	68.500.000
11	Pontificia Universidad Católica de Chile	Alessio Bellino	Ventana Celeste: Astronomía Inmersiva y Accesible para Todos	3	19.998.000
12	Pontificia Universidad Católica de Chile	Julio Chanamé Domínguez	The Impact of the Magellanic Clouds Passing Through the Milky Way Halo	1	68.500.000
13	Universidad de Concepción	Rodrigo Andrés Reeves	Development of a new 183 GHz Water Vapor Radiometer with profiling capabilities	4	83.694.106
14	Universidad Técnica Federico Santa María	Yara Lorena Jaffé Ribbi	Reconstructing the Environmental History of Galaxies in Clusters	1	68.500.000
15	Universidad de Valparaíso	Alfredo Vega	Club de Lectura Astronómica 60+	3	15.775.00
16	Universidad Técnica Federico Santa María	Alejandra Rojas Lilayú	Astroacuarela: Pigmentos del Universo	3	7.864.380

Type*

Postdoctoral programmes in astronomy at Chilean institutions.
Support for academic institutions through the funding of positions for tenured, associate or assistant professors for periods of up to two years at Chilean institutions.
Pilot training programmes for the teaching and dissemination of astronomy in Chile.
Projects for the development and construction of technological systems for astronomy.
Extended scientific visits by postdoctoral fellows, researchers or academics from Chilean academic institutions.
Projects for the development of astronomy in areas not covered by the above categories.

New SOXS instrument ready to observe fleeting cosmic events

Tue, 16 Dec 2025 16:00:00 +0100

ESO’s new facility, SOXS (Son Of X-Shooter), has successfully made its first observations at the La Silla Observatory in Chile. The spectrograph can be flexibly and rapidly scheduled to make observations of time-critical astronomical events, such as gamma-ray bursts, supernovae, and asteroids passing close to Earth.

From its new home on ESO’s 3.58-metre New Technology Telescope (NTT, pictured above), SOXS is a unique spectrograph that can be used to quickly observe transient cosmic events, at large distances or closer to home. Designed to see, simultaneously, in both optical and near-infrared wavelengths, SOXS is inspired by the X-shooter instrument currently operating on ESO’s Very Large Telescope.

“SOXS was conceived 10 years ago in view of what is now called time-domain astronomy,” says the project’s Principal Investigator Sergio Campana of the Brera Astronomical Observatory, Italy’s National Institute for Astrophysics (INAF). “After years of hard work, we are now positioned to play a major role in the study of astrophysical transients.”

Transients are astronomical phenomena that occur, or change in brightness or appearance, on relatively short timescales. This includes supernovae explosions, stars pulled apart by supermassive black holes, bursts of gamma-rays in the very distant Universe and fast-moving asteroids in our Solar System, all of which SOXS will study. Like X-shooter at the VLT, the instrument will have a wide variety of applications, but SOXS was specifically designed to conduct follow-up observations of transient events found in wide-field imaging or following real-time alerts sent to the astronomical community after specific cosmic events.

Since transient events last only a fleeting moment, which can be as short as a few milliseconds, it is critical that discoveries of these cosmic phenomena are followed up within minutes or hours by dedicated instruments. The nature of these objects will also change with time, sometimes dramatically so. To study and understand these changes, astronomers need uninterrupted follow-up over time with a dedicated instrument and telescope, something which is not commonly available given the demand for observing time on professional telescopes. SOXS on the NTT will fill this missing gap and provide unprecedented continuous coverage of these elusive, yet fascinating, astronomical objects.

“Specialising a medium-sized telescope like the NTT to a specific task like chasing transients is key to success,” says SOXS Project Manager Pietro Schipani of INAF Capodimonte Astronomical Observatory. “We are very proud of the people who have been working for many years to make our dream come true.”

SOXS simultaneously replaces NTT’s two previous spectrographs SOFI (Son of Isaac) and EFOSC2 (ESO Faint Object Spectrograph and Camera 2). “Effectively, it is two instruments in one”, says SOXS Instrument Scientist Paolo D’Avanzo of INAF-Brera, “with a double spectrograph designed to cover the whole optical and near-infrared wavelength range in a single shot, significantly increasing the efficiency of the NTT.” This device works similarly to how a prism splits light, allowing astronomers to unveil the characteristics of the events observed, such as the chemical composition or the distance to the source. Besides, it will also allow observations in imaging mode in the optical bands. The instrument is undergoing the final commissioning phase at the telescope under the supervision of the ESO team, ahead of starting the scientific observations of both the consortium and the wider ESO community.

More Information

The SOXS consortium consists of:

Italy: INAF (Osservatorio astronomico di Brera, Osservatorio astronomico di Capodimonte, Osservatorio astronomico di Padova, Osservatorio astronomico di Catania, Osservatorio astronomico di Roma and Fundación Galileo Galilei) — consortium leader
Israel: The Weizmann Institute and Tel Aviv University
UK: Queen’s University Belfast and University of Oxford
Finland: University of Turku and Finnish Centre for Astronomy with ESO (FINCA)
Chile: Millennium Institute of Astrophysics
Denmark: The Niels Bohr Institute and Aarhus University

ESO becomes a partner in the IAU Centre for the Protection of the Dark and Quiet Sky

Wed, 10 Dec 2025 14:00:00 +0100

Yesterday, ESO signed an agreement with the International Astronomy Union (IAU)’s Centre for the Protection of the Dark and Quiet Sky (CPS) to become a contributing partner. The agreement was signed by the ESO Director General Xavier Barcons and Piero Benvenuti, IAU CPS Director during a high-level event on the protection of astronomical sites in Vienna.

“This signing underscores ESO’s unwavering commitment to the protection of the sky above astronomical observatory sites. We are proud to join our partners at the IAU CPS in the fight against light pollution and satellite interference,” Barcons said.

Remote locations with pristine dark skies, ideal for most astronomical observations, are increasingly at risk from light pollution due to the urban growth of cities and industrial complexes near the observatories. An acute example is the threat of INNA, an industrial project planned to be located just a few kilometres away from the telescopes of ESO’s Paranal Observatory. In addition, in recent years a new threat has emerged: the large number of satellites being introduced into low-Earth orbits, which affect astronomical observations both due to their bright appearance and their transmissions, which can affect the measurements made by highly sensitive radio telescopes.

The CPS brings together astronomers, satellite operators, policy makers and other stakeholders to "coordinate efforts and unify voices across the global astronomical community with regard to the protection of the dark and quiet sky from satellite constellation interference,” as stated on their website. ESO now joins the centre’s two founding partners, the US national centre for ground-based, night-time optical astronomy NSF NOIRLab and the SKA Observatory (SKAO), an intergovernmental organisation dedicated to promoting global collaboration in radio astronomy, as a formal partner of the institution. The agreement means ESO will dedicate personnel and resources to the IAU CPS, while having an active role in the centre’s decision-making process.

The event and agreement signing took place on sidelines of a joint United Nations–SKAO workshop on “Dark and Quiet Skies for Science and Society".