What is it about?

Much of the Universe's raw material, such as cold gas, dust and the clouds where stars are born, is invisible to ordinary telescopes. It glows mainly in millimetre and submillimetre waves, a kind of light somewhere between infrared and radio. Today's telescopes for this light either see very sharply but only a tiny patch of sky at a time, or see large areas but blurrily. AtLAST (the Atacama Large Aperture Submillimeter Telescope) is a proposed 50-metre dish in the Chilean Atacama desert, designed to do both. It could scan a patch of sky about four times the width of the full Moon, quickly, while still picking out fine detail. This paper reports where the design stands after the first European-funded design study, and what the follow-up project (2025–2028) is working on. The telescope has to stay precise to a fraction of the width of a human hair while the huge dish is exposed to wind and moves quickly. The paper describes how a curved "rocking chair" mount and a surface that continuously adjusts its own shape make that possible. It also describes the work to choose between two candidate sites, which includes two 24-metre weather towers that have been measuring wind since 2023. Computer simulations of a nearby galaxy show what this buys. AtLAST would capture the galaxy and its surroundings in about 20 minutes. Ten hours of observing with today's best arrays would miss much of the faint, spread-out gas, and for some types of light would miss more than 90% of it.

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Why is it important?

Among the missing "ordinary" matter in the Universe, a large part is thought to be hiding in diffuse gas around galaxies, which today's instruments struggle to see. The telescope would also serve other fields, including star and galaxy formation, the Sun and space weather, and fast-changing events in the sky. AtLAST is also meant to be the first climate-neutral modern research facility. It would run off the grid on solar power with batteries and hydrogen storage, which is estimated to cut its carbon footprint by 95% compared with business as usual. When the dish brakes, a system like the ones in hybrid cars would recover the energy, and simulations show this cutting the drives' demand on the power supply by about 56%. The team has also been interviewing communities and authorities in northern Chile about what sustainability should mean for them, including whether the project could share surplus power. The aim is a template for building large science facilities that treat the people and environment around them as partners.

Perspectives

I contribute to designing how AtLAST will be operated around the clock, 24 hours a day. We envision a distributed system in which teams of astronomers and operators observe from different regions of the world during their normal office hours, handing over to colleagues in other time zones as the day moves around the globe. This avoids regular long-distance travel and the need for people to live and work in the high-altitude desert. That is better for safety and for the environment, and it supports a healthier work-life balance. One of the biggest challenges we face is data. Because AtLAST can image such a large area of sky at once, it will collect enormous volumes of data, and we have to work out how to store, process and share it so that scientists anywhere can use it. Rather than sending huge files to each user, we are planning to bring users to the data, through a central science archive and remote analysis tools. I feel very proud, and very much at home, contributing to this project. It is a privilege to be part of such an enthusiastic and vibrant international team.

Francisco Miguel Montenegro Montes

Read the Original

This page is a summary of: The Atacama Large Aperture Submillimeter Telescope (AtLAST): enabling large-scale sub-mm science beyond 2030, August 2026, SPIE,
DOI: 10.1117/12.3104538.
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