Japan just switched on the world’s highest telescope. This week marks the “first light” for the University of Tokyo Atacama Observatory (TAO), built on the summit of a desert mountain in northern Chile at a whopping 18,504 feet (5,640 meters).
TAO is a groundbreaking telescope, partly funded by the Japanese government. Perched atop the summit of Cerro Chajnantor in northern Chile’s Atacama desert—one of the driest and highest places on Earth—it is a 6.5-meter aperture telescope designed to see into the infrared.
TAO will be the only ground-based telescope in the world capable of clearly viewing mid-infrared wavelengths—something only space telescopes can currently offer.
Location Is Everything
TAO’s location is critical. Light comes from the distant universe in different wavelengths: radio, infrared, optical (visible), X-ray and gamma-ray. The longer wavelengths of infrared light are critical for astronomy but are absorbed by the water in Earth’s atmosphere and impossible to observe from ground level. TAO can detect infrared and visible light by getting above most of the atmosphere.
“It contains state-of-the-art optics, sensors, electronics and mechanisms, but the uniquely high altitude of 5,640 meters is what gives TAO such clarity of vision,” said Yuzuru Yoshii, an emeritus professor who has been the principal investigator of TAO since 1998. At that height, there’s little moisture in the atmosphere to impact its infrared sight.”
Huge Challenges
TAO is also away from any discernable light pollution—an increasingly rare claim even for a professional telescope. TAO is just three miles (five kilometers) from the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescopes.
The product of 26 years of planning, getting TAO to “first light” has been hugely challenging. “Construction on the summit of Cerro Chajnantor was an incredible challenge, not just technically, but politically too,” said Yoshii. “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 safely work at that altitude.”
At such a height, the risk of altitude sickness is high not only for construction workers but also for the engineers and astronomers who will work there.
Explain The Unexplained
It’s hoped that TAO’s mid-infrared capabilities—alongside its availability, unlike time on oversubscribed space telescopes like Hubble and Webb— will allow astronomers to closely study everything from the environments around stars—including planet-forming regions—to cosmic dust. “New telescopes and instruments naturally help advance astronomy,” said Masahiro Konishi, an assistant professor working on TAO. “I hope the next generation of astronomers use TAO … to make unexpected discoveries that challenge our current understanding and explain the unexplained.”
Wishing you clear skies and wide eyes.
