Dark skies of Paranal Observatory in Chile are under threat
The European Southern Observatory’s Paranal Observatory lies under some of the darkest and clearest skies in the world, in Chile’s Atacama Desert. Now a new construction project is threatening to cause irreparable damage to the views of deep space, visible from this pristine site. In this image, Jupiter is the bright object near ESO Photo Ambassador Petr Horálek (standing at center). The telescopes in this view are the 4 Unit Telescopes (UTs) that comprise ESO’s Very Large Telescope VLT. Also in this shot are 4 smaller Auxiliary Telescopes (ATs). Image via ESO/ P. Horálek. Dark skies of Paranal Observatory under threat The night sky over the European Southern Observatory’s Paranal Observatory in Chile is said to be the darkest and clearest over any astronomical observatory in the world. Astronomical data gathered under these pristine skies let astronomers present the first image of an exoplanet, and confirm the accelerated expansion of the universe. But now, according to ESO, a new industrial megaproject is threatening the observatory’s dark skies. A preliminary analysis by ESO suggests the project would cause “devastating and irreversible” harm to the region’s night sky. That megaproject is a massive industrial complex by AES Andes, based in Santiago, Chile. This company is a subsidiary of the U.S. power company AES Corporation. According to ESO, the AES Andes complex would be city sized (more than 7,400 acres) and lie just a few kilometers from Paranal Observatory. The ESO analysis follows an environmental assessment, submited by AES Andes on December 24, 2024. AES Andes’ project is called INNA, for Infraestructura Energética para la Generación de Hidrogeno y Amoníaco Verde. The project seeks to make use of the solar and wind resources in the area. ESO’s director general Xavier Barcons said: The proximity of the AES Andes industrial megaproject to Paranal poses a critical risk to the most pristine night skies on the planet. Dust emissions during construction, increased atmospheric turbulence, and especially light pollution will irreparably impact the capabilities for astronomical observation, which have thus far attracted multi-billion-Euro investments by the governments of the ESO Member States. View larger. | This map of the region shows the location of Paranal Observatory in the Atacama Desert in Chile along with the proposed industrial complex. Image via ESO. The results of the analysis The INNA project would include construction of a port, ammonia and hydrogen production plants and thousands of electricity generation units. The analysis said that light pollution would increase by at least 35% above the VLT and by more than 50% above the south site of the Cherenkov Telescope Array Observatory (CTAO-South). The increase in air turbulence and vibrations would further cause problems. For example, the Extremely Large Telescope, currently under construction, is extremely sensitive to even the smallest vibrations. The nearby INNA project wind turbines would impair its abilities. How would this harm astronomers’ research? One example – described by Paul Scott Anderson of EarthSky – is that, after its completion, the ELT would have the capability to find alien life in just hours. Will that still be true if AES Andes carries out its industrial megaproject? The impact of light pollution on these telescopes even puts our planet at risk. A representative of ESO, Itziar de Gregorio-Monsalvo, said: With a brighter sky, we severely limit our ability to … monitor asteroids that could cause damage to our planet. We build the largest and most powerful telescopes, in the best place on Earth for astronomy, to enable astronomers worldwide to see what no one has ever seen before. Light pollution from projects like INNA doesn’t just hinder research, it steals our shared view of the universe. The director of operations for ESO, Andreas Kaufer, said: The light-pollution figures we are reporting assume that the project will install the most modern available luminaries in a way that minimizes light pollution. However, we are concerned that the inventory of light sources planned by AES is not complete and fit for purpose. In that case, our already alarming results would underestimate the potential impact of the INNA project on the Paranal sky brightness. Request to move the project Barcons said: ESO and its Member States are fully supportive of energy decarbonization. For us Chile should not have to make a choice between hosting the most powerful astronomical observatories and developing green-energy projects. Both are declared strategic priorities by the country and are fully compatible — if the different facilities are located at sufficient distances from one another. ESO also has an executive summary of the report on the environmental impact assessment. ESO said: The relocation of this project remains the only effective way to prevent irreversible damage to Paranal’s unique skies. Chilean authorities will look at the full technical report in late April 2025. Views from Paranal Observatory This image showcases ESO’s Paranal Observatory and the Very Large Telescope (VLT). They sit at an altitude of 8,530 feet (2,600 meters) in the Atacama Desert in Chile. The snow-capped peak in the background is the volcano Llullaillaco, on the Argentinean border. ESO said, “This image is a testimony of the magnificent quality of the air and the ideal conditions for observing at this remote site.” Image via ESO/ G.Hüdepohl. A laser shoots out of one of the Unit Telescopes of the Very Large Telescope (VLT). Image via ESO/ Yuri Beletsky. This scene from Paranal Observatory shows an Auxiliary Telescope in the foreground between the Magellanic Clouds as the Milky Way arches overhead. Image via ESO/ R. Wesson. Bottom line: The Atacama Desert in Chile, where ESO’s Paranal Observatory sits, has some of the clearest and darkest skies in the world. Groundbreaking astronomical discoveries have come from the observatories there. But a new industrial complex threatens the observatory with devastating and irreversible impacts. Via ESOThe post Dark skies of Paranal Observatory in Chile are under threat first appeared on EarthSky.
ESO's Paranal Observatory, in Chile's Atacama Desert, has some of the world's clearest and darkest skies. But a new construction project now threatens them. The post Dark skies of Paranal Observatory in Chile are under threat first appeared on EarthSky.

Dark skies of Paranal Observatory under threat
The night sky over the European Southern Observatory’s Paranal Observatory in Chile is said to be the darkest and clearest over any astronomical observatory in the world. Astronomical data gathered under these pristine skies let astronomers present the first image of an exoplanet, and confirm the accelerated expansion of the universe. But now, according to ESO, a new industrial megaproject is threatening the observatory’s dark skies. A preliminary analysis by ESO suggests the project would cause “devastating and irreversible” harm to the region’s night sky.
That megaproject is a massive industrial complex by AES Andes, based in Santiago, Chile. This company is a subsidiary of the U.S. power company AES Corporation. According to ESO, the AES Andes complex would be city sized (more than 7,400 acres) and lie just a few kilometers from Paranal Observatory. The ESO analysis follows an environmental assessment, submited by AES Andes on December 24, 2024.
AES Andes’ project is called INNA, for Infraestructura Energética para la Generación de Hidrogeno y Amoníaco Verde. The project seeks to make use of the solar and wind resources in the area.
ESO’s director general Xavier Barcons said:
The proximity of the AES Andes industrial megaproject to Paranal poses a critical risk to the most pristine night skies on the planet. Dust emissions during construction, increased atmospheric turbulence, and especially light pollution will irreparably impact the capabilities for astronomical observation, which have thus far attracted multi-billion-Euro investments by the governments of the ESO Member States.

The results of the analysis
The INNA project would include construction of a port, ammonia and hydrogen production plants and thousands of electricity generation units. The analysis said that light pollution would increase by at least 35% above the VLT and by more than 50% above the south site of the Cherenkov Telescope Array Observatory (CTAO-South). The increase in air turbulence and vibrations would further cause problems. For example, the Extremely Large Telescope, currently under construction, is extremely sensitive to even the smallest vibrations. The nearby INNA project wind turbines would impair its abilities. How would this harm astronomers’ research? One example – described by Paul Scott Anderson of EarthSky – is that, after its completion, the ELT would have the capability to find alien life in just hours. Will that still be true if AES Andes carries out its industrial megaproject?
The impact of light pollution on these telescopes even puts our planet at risk. A representative of ESO, Itziar de Gregorio-Monsalvo, said:
With a brighter sky, we severely limit our ability to … monitor asteroids that could cause damage to our planet. We build the largest and most powerful telescopes, in the best place on Earth for astronomy, to enable astronomers worldwide to see what no one has ever seen before. Light pollution from projects like INNA doesn’t just hinder research, it steals our shared view of the universe.
The director of operations for ESO, Andreas Kaufer, said:
The light-pollution figures we are reporting assume that the project will install the most modern available luminaries in a way that minimizes light pollution. However, we are concerned that the inventory of light sources planned by AES is not complete and fit for purpose. In that case, our already alarming results would underestimate the potential impact of the INNA project on the Paranal sky brightness.
Request to move the project
Barcons said:
ESO and its Member States are fully supportive of energy decarbonization. For us Chile should not have to make a choice between hosting the most powerful astronomical observatories and developing green-energy projects. Both are declared strategic priorities by the country and are fully compatible — if the different facilities are located at sufficient distances from one another.
ESO also has an executive summary of the report on the environmental impact assessment. ESO said:
The relocation of this project remains the only effective way to prevent irreversible damage to Paranal’s unique skies.
Chilean authorities will look at the full technical report in late April 2025.
Views from Paranal Observatory



Bottom line: The Atacama Desert in Chile, where ESO’s Paranal Observatory sits, has some of the clearest and darkest skies in the world. Groundbreaking astronomical discoveries have come from the observatories there. But a new industrial complex threatens the observatory with devastating and irreversible impacts.
The post Dark skies of Paranal Observatory in Chile are under threat first appeared on EarthSky.