Imma Perfetto
Cosmos science journalist
The University of Tokyo Atacama Observatory (TAO) is the highest astronomical observatory in the world as certified by the Guinness World Record.
TAO sits at an altitude of 5,640m on the summit of a mountain in northern Chile’s Atacama Desert.
The 6.5m infrared-optimised telescope is finally up and running after 26 years of planning and construction.
It’s unique elevation – 440m higher than the next highest observatory – will afford astronomers unrivalled clarity of vision to study the cosmos in the infrared.
“I’m seeking to elucidate mysteries of the universe, such as dark energy and primordial first stars. For this, you need to view the sky in a way that only TAO makes possible,” says astronomer Yuzuru Yoshii, who has led the TAO project as principle investigator since 1998.
“At that height, there’s little moisture in the atmosphere to impact its infrared sight.”
Water vapour absorbs incoming electromagnetic radiation, but particularly infrared light, so TAO has been built at a location that has less water vapor in the atmosphere than any other place on Earth.
Takashi Miyata, director of the Atacama Observatory of the Institute of Astronomy and manager of TAO’s construction, says: “thanks to the height and arid environment, TAO will be the only ground-based telescope in the world capable of clearly viewing mid-infrared wavelengths.
“This area of the spectrum is extremely good for studying the environments around stars, including planet-forming regions.
“I’ve been involved with TAO for [more than] 20 years; as an astronomer, I am very excited indeed and the real work, of making observations, is about to begin.”
According to Yoshii, construction on the summit of Cerro Chajnantor was an incredible challenge, not just technically, but politically too.
“I have liaised with Indigenous peoples to ensure their rights and views are considered, the Chilean government to secure permission, local universities for technical collaboration, and even the Chilean Health Ministry to make sure people can work at that altitude in a safe manner.”
The risk of altitude sickness is high for construction workers and astronomers, especially at night when some symptoms can worsen. A base facility has been constructed in San Pedro de Atacama, about 50km from the summit, for remote operation of the telescope.
