Dark Skies Council: International astronomical observatories join forces to protect Chile's skies

Faced with the growing risk that light pollution represents for the development of astronomy in Chile, the main international observatories with a presence in the country have formed a joint organization dedicated to protecting the dark skies of northern Chile. The council will act through Fundación Cielos de Chile and the Office for the Protection of the Quality of the Northern Chilean Sky (OPCC), with the objective of coordinating strategies and articulating actions in the face of the advance of light pollution. 

Light pollution is increasing by 9.6% each year, according to a study published in Science magazine. Chile’s skies are also being affected by this phenomenon and it is estimated that a 10% increase in sky brightness would mean a loss of 12.07% of the original capacity of the optical telescopes located in the country. 

In response to this problem, the Association of Universities for Research in Astronomy (AURA), the Giant Magellan Telescope (GMT), the European Southern Observatory (ESO) and the Las Campanas Observatory of the Carnegie Institution for Science, signed an agreement to create the Dark Skies Council. Through this alliance, the institutions will work in a coordinated manner to protect Chile’s privileged skies. 

The signatory institutions manage some of the largest and most advanced optical observatories in the world, all of them located in Chile: AURA is in charge of the Cerro Tololo Observatory, Gemini South and the under-construction Vera C. Rubin Observatory; the Giant Magellan Telescope (GMT), also under construction, will be installed at Las Campanas, where the Carnegie Science Institution currently operates its observatory; while ESO operates observatories at Paranal and La Silla, and will soon operate the Extremely Large Telescope (ELT) under construction at Cerro Armazones. 

The importance of caring for dark skies 

Thanks to the exceptional quality of its skies, Chile today concentrates nearly 40% of the world’s astronomical observation capacity. In the last two decades, the number of astronomical institutions has doubled in the country, and the number of people dedicated to this science has tripled. In addition, three mega-telescopes will be installed in the coming years, which will be among the largest in the world, with a total investment of more than 5 billion dollars. Their operation will allow Chile to exceed 60% of the global astronomical observation capacity by 2030. 

However, this leadership is at risk. The sustained increase of light pollution sources from urban centers, industrial and mining operations, ports and highways threatens the natural darkness of the night sky in the regions of Antofagasta, Atacama and Coquimbo, key areas for astronomy. “The quality and darkness of the night sky are fundamental to the scientific operations of our observatories. The preservation of the dark skies of northern Chile is a priority for the signatory institutions, since the continuity of their present and future activities depends on it,” states the signed agreement.   

What is the Dark Skies Council and who are its members? 

The Dark Skies Council is composed of six representatives of the observatories and its main mission will be to define and monitor the implementation of a common strategy to protect dark skies. Its functions include coordinating activities with the Office for the Protection of Sky Quality in Northern Chile (OPCC) and Fundación Cielos de Chile, as well as the management and allocation of resources to implement concrete initiatives in the territory.  

The OPCC works for the protection of dark skies, essential for astronomy, and provides technical support to facilitate the implementation of light pollution regulations in the regions of Antofagasta, Atacama and Coquimbo. For 25 years it has collaborated with municipalities, local communities and regional actors to promote actions for the prevention and reduction of this type of pollution.  

For its part, the work of Fundación Cielos de Chile has focused on the conservation of the night skies as the country’s natural, scientific and cultural heritage, and promotes the responsible use of artificial light for the benefit of science, biodiversity, human health and sustainable tourism.  

The Council appointed Oscar Contreras, who is GMT’s Vice President and Representative in Chile, as its first Director. Contreras has extensive experience at the intersection of science, public policy and conservation.  

Thus, as Chile strengthens its leadership in dark skies protection, the launch of the Dark Skies Council marks a new era characterized by proactive stewardship to preserve one of Earth’s most important windows to the cosmos. 

About AURA 

The Association of Universities for Research in Astronomy (AURA) is a non-profit organization founded in 1957 in the United States and is composed of 49 U.S. institutions and 3 international affiliates, including the University of Chile and the Pontificia Universidad Católica de Chile. 

AURA is a scientific institution that builds, maintains and operates world-class ground-based optical telescope facilities for the U.S. National Science Foundation (NSF) through the NSF NOIRLab center and the National Solar Observatory (NSO). For NASA, AURA manages the Space Telescope Science Institute (STScI). 

NSF NOIRLab is the leading U.S. national center for ground-based astronomy in the optical and infrared range. In Chile it manages the Cerro Tololo Inter-American Observatory (CTIO), Gemini South of the Gemini International Observatory, and the Vera C. Rubin Observatory (currently under construction). Rubin Observatory (currently under construction). NSF NOIRLab enables the diverse and inclusive astronomical community to advance humanity’s understanding of the Universe by developing and operating state-of-the-art ground-based observatories and providing data products and services to the entire community. 

About ESO  

The European Southern Observatory (ESO) provides the global scientific community with the means to unlock the secrets of the Universe for the benefit of all. We design, build and operate state-of-the-art ground-based observatories – used by the astronomical community to address exciting questions and spread the fascination of astronomy – and promote international collaboration in astronomy. Established as an intergovernmental organization in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Ireland, Italy, Netherlands, Poland, Portugal, Spain, Sweden, Switzerland, United Kingdom and United States), with Chile as host country and Australia as a strategic partner. ESO’s headquarters and its planetarium and visitor center, the ESO Supernova, are located near Munich (Germany), while the Chilean Atacama Desert, a wonderful place with unique conditions for observing the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope together with its interferometer VLTI (Very Large Telescope Interferometer), and survey telescopes such as VISTA. Also at Paranal, ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. At Chajnantor, together with international partners, ESO operates ALMA, a facility that observes the skies in the millimeter and submillimeter range. On Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky“: the ESO Extremely Large Telescope (ELT). From our offices in Santiago (Chile), we support the development of our operations in the country and are committed to Chilean partners and Chilean society. 

About the Giant Magellan Telescope 

The Giant Magellan Telescope is the future of space exploration from Earth. It will have seven of the world’s largest mirrors, which will form a 25.4-meter telescope to produce images of the Universe with an unprecedented level of detail. It will shed new light on the cosmic mysteries of dark matter, investigate the origins of chemical elements and confirm, for the first time, the existence of signs of life on distant planets. The Giant Magellan Telescope is a project of the GMTO Corporation, an international consortium of 14 universities and research institutions representing the United States, Australia, Brazil, Chile, Israel, South Korea and Taiwan. The telescope is being built in the United States and will be assembled in Chile in the early 2030s. Learn more about The Universe Awaits at giantmagellan.org. 

About Las Campanas Observatory 

Carnegie Science’s Las Campanas Observatory in Chile provides the scientific community with access to world-class telescopes with views of the Magellanic clouds and the entire southern sky. Carnegie Science is headquartered on Broad Branch Road in Washington, D.C., with three research divisions on both coasts of the United States and Las Campanas Observatory in Chile. It is a nonprofit, independent, endowed organization under the direction of President John Mulchaey. Carnegie Science empowers its researchers to answer the most important questions of our time, making discoveries that transform our understanding of life, the planets and the universe at large. The research breakthroughs made have radically changed the way we understand science.