The highest observatory in the world just opened in Chile

The University of Tokyo Atacama Observatory (TAO) officially opened on Tuesday after 26 years of planning and construction. Sitting 18,500 feet high on Mount Chajnantor in the Atacama Desert in Chile, the 6.5-meter optical-infrared TAO telescope is now the highest in the world.

TAO replaces a smaller version of itself called MiniTAO, which held the highest telescope distinction before it. It beats the Chacaltaya Observatory, owned by the University of Madrid and sitting 17,191 feet on Mount Chacaltaya in Bolivia.

The next three record holders in the top five are also in Chile’s Atacama desert: the James Ax Observatory (17,100 feet); the Atacama Cosmology Telescope (17,030 feet); and the Llano de Chajnantor Observatory (sources vary; about 16,700 feet). Many of the world’s major observatories are built in the high-altitude, northeastern area of Chile, near Bolivia, because of its clear skies. The country’s tax exemptions for such projects help, too.

Being so high up means far less moisture in the air; TAO can observe “almost the entire range of near-infrared wavelengths,” including mid-infrared. No other earthbound telescope can do that, Phys.org notes. The University of Tokyo writes that such terrestrial observatories are capable of taking higher-resolution shots of space, thanks to their larger apertures, than their space-based counterparts. The telescope will be used to learn about “the birth of galaxies and the origin of planets” starting in 2025, according to the University of Tokyo’s announcement.

There’s a thought it could also improve on observations from the nearby ALMA telescope by viewing the same objects in different wavelengths to give researchers new insights.

The benefits of TAO sitting at such an extreme altitude come at a cost, however, as humans are pretty ill-suited for life that high up. Yuzuru Yoshii, the principal investigator who started the project in 1998, said that builders working on the telescope needed medical checkups and had to regularly inhale oxygen while they worked.

As Phys.org notes, even the researchers working inside will need to take precautions to stay healthy in the face of altitude sickness. The team plans to eventually operate the telescope remotely from a lower base facility to avoid such issues.

Besides ALMA, TAO joins other Atacama-based observatories like the European Extremely Large Telescope on the top of Cerro Armazones and the European Very Large Telescope that sits atop Cerro Paranal.