It is in this scenario that the Pico dos Dias Observatory (OPD) operates, the largest astronomical complex in operation in Brazil. Installed at an altitude of 1,864 meters, the observatory monitors stars, galaxies, exoplanets, asteroids, comets and even fragments of deactivated satellites, known as space debris.
Over more than four decades, the structure participated in research that expanded knowledge about small bodies in the Solar System, including studies related to the rings of Chariklo and the confirmation of the rings of Chiron, an object located between the orbits of Saturn and Uranus.
A window to the Universe 🌌
Access to the observatory starts from the Bom Sucesso neighborhood, in Brazópolis, and takes around 25 to 35 minutes by car along a mountain road to the top of Serra da Mantiqueira.
In winter, especially during the early morning hours, the cold is one of the challenges of the operation. Temperatures can be close to 2°C, with a thermal sensation reaching -1°C.
The altitude is precisely one of the main reasons for choosing the location. With less interference from the atmosphere, dust, humidity and light pollution, telescopes are able to capture more precise signals from space.
"Being high on the mountain means that our telescopes are above most of the layers of dust, pollution and denser air. The altitude provides a cleaner and more stable sky, essential for capturing deep images of the Universe", explains Carlos Eduardo Lisboa da Silva, instrumentation technician.
In addition to the natural conditions, the location was also strategic due to its proximity to important research centers, such as São Paulo, Rio de Janeiro, Belo Horizonte and Itajubá.
Telescopes don't just 'zoom' 🔭
Anyone who imagines an astronomer observing the sky through the lens of a telescope as he appears in films is often surprised to learn about the observatory's routine.
Today, most of the work takes place with scientific equipment and computers that transform captured light into data.
"Many people imagine that the astronomer spends the night looking directly through the telescope. Today, most of the work takes place in front of computers and scientific instruments. The telescope collects the light from celestial objects and we transform this information into data that helps to understand the Universe", explains Luciano Fraga, deputy director of the National Astrophysics Laboratory (LNA), a unit linked to the Ministry of Science, Technology and Innovation (MCTI), responsible for operating the observatory.
The complex's main equipment is the Perkin-Elmer telescope, with a 1.6 meter diameter mirror, considered the largest optical telescope in operation in Brazil.
The observatory also houses the Boller & Chivens, Zeiss and ROBO43 telescopes. The Zeiss carries a historical curiosity: purchased from the former East Germany in the 1970s, part of the payment was made with Brazilian coffee.
"It wasn't bought with money. Brazil paid for it using coffee. It's a story that shows how Brazilian astronomy needed to find creative ways to build its scientific infrastructure", says Carlos.
Nights of science while Brazil sleeps 🌙
Before dark, researchers and technicians begin preparing the equipment. Calibrations, weather conditions checks and adjustments are made so that the telescopes can operate during the early hours of the morning.
It was on one of these nights that astronomer Bárbara Luiza de Miranda Marques decided to pursue a career.
"My first experience at the Pico dos Dias Observatory was accompanying a colleague on a galaxy observation project. It was quite cold, but seeing the Milky Way crossing the sky was unforgettable. After that experience, I was sure that I had chosen the right profession."
Today, a researcher at LNA, she explains that observation is just one stage of the work.
"There is a lot of work before and after the night of observation. There is the preparation of projects, the competition for telescope time, the collection of data and then the entire stage of processing and analyzing this information."
Each semester, between 20 and 25 scientific projects use the observatory's equipment. The research brings together teams from Brazilian universities and institutes, as well as international collaborators.
From stars to planets ⭐
Pico dos Dias telescopes are used to study different objects in the Universe: stars, distant galaxies, asteroids, comets and exoplanets — planets that orbit stars other than the Sun.
Many discoveries arise from small changes in the light captured by instruments.
"Most people imagine that we point the telescope and see the round planet in the image. But they are so far away and are so obscured by the brightness of the stars that we use light tricks to find them", explains Carlos.
One of these methods is planetary transit. When a planet passes in front of its star, it causes a small reduction in the observed brightness.
"It's as if an insect passed in front of a very distant spotlight. You can't see the insect, but you notice a small reduction in the light", he compares.
In addition to traditional astronomy, the observatory also contributes to the monitoring of artificial objects in space, such as deactivated satellites and fragments in Earth's orbit.
Discovery of the rings 🪐
One of the most notable studies involving the observatory involved Chariklo, a small body located between Saturn and Uranus.
In 2013, researchers followed Chariklo's passage in front of a star and realized that there was something beyond the object itself blocking the observed light.
"As we analyzed the data, we realized that there was something other than Chariklo blocking the star's light. When we understood that they were rings, it became clear that we were facing a discovery that no one expected", says Felipe Braga-Ribas, professor at the Federal Technological University of Paraná (UTFPR) and leader of the research.
The Pico dos Dias Observatory participated in the observations that helped researchers confirm that Chariklo, a small body in the Solar System, has rings.
The Pico dos Dias Observatory helped characterize the star hidden by the object, contributing to the analysis of the phenomenon.
Years later, the complex played a fundamental role in confirming Chiron's rings. The observations carried out in the South of Minas helped to prove the existence of three rings and a disc of material around the celestial body.
"If we hadn't had the observations made at Pico dos Dias, we wouldn't have been able to make this new confirmation."
Today, at least four small bodies in the Solar System are known to have ring systems.
More than four decades of science 📚
The scientific production of the observatory helps to assess the importance of the structure:
Over the history of OPD, the data collected has resulted in 605 articles published in peer-reviewed scientific journals.
The complex also contributed to the training of 110 doctors and 140 masters.
Around 40 professionals work at the site, including researchers, technicians, operators and support teams.
Each semester, the telescopes carry out between 140 and 150 nights of observation, with utilization between 60% and 80%, depending on climatic and technical conditions.
Maintaining a scientific structure of this size in an isolated area requires constant operation. During the early hours of the morning, around five professionals are responsible for operating the equipment, monitoring observations and supporting researchers.
"Undoubtedly, the logistics. Maintaining supplies, internet, energy, water and even carrying out new constructions is a very complex operation due to the fact that it is an isolated location and difficult to access", says Carlos.
The weather also directly impacts work. "Rain, clouds that cover the sky and high humidity are the most common causes that force us to close the domes."
The observatory is going through a modernization phase, with plans for new telescopes, expansion of remote observations and more automated systems. Three of the five new pieces of equipment planned have already been acquired by the LNA.
Future of Brazilian astronomy 🚀
Even with the advancement of technology, human presence remains essential for the observatory to function. Technicians, operators and researchers monitor observations, adjust equipment and transform signals from space into scientific knowledge.
For Bárbara, it is precisely this connection between technology and curiosity that keeps astronomy alive. At the top of Mantiqueira, the South of Minas keeps an open window to the Universe in search of answers and, sometimes, discoveries that no one expected to find.
"When most people are sleeping, we are following phenomena that happened thousands or millions of years ago. It's an experience that constantly reminds us how vast the Universe is and how much we still have to discover."
