ALMA Breaks Observation Record for the Second Consecutive Year

• For the second year in a row, ALMA reached a new record of observing hours, delivering 4,496 hours of science-quality data with its 12-meter Array — the highest in its history.
• The observatory also achieved 4,201 hours on the 7-meter Array and 3,240 hours on the Total Power Array, setting new benchmarks across its entire system.
• Despite facing the harshest winter in nearly a decade on the Chajnantor plateau, ALMA’s teams demonstrated exceptional resilience and efficiency.

The Atacama Large Millimeter/submillimeter Array (ALMA) has once again surpassed its own record. In Cycle 11, the observatory delivered an unprecedented 4,496 hours of science-quality data on the 12-meter Array — exceeding the 4,250 hours achieved in Cycle 10. This marks the second consecutive year in which ALMA has set a new benchmark for observing time, highlighting its consistent improvement and commitment to maximizing scientific return.

Meanwhile, the 7-meter Array and Total Power Array achieved 4,201 and 3,240 hours, respectively — both record figures. These results confirm that every part of the ALMA system is operating at peak performance, ensuring that astronomers worldwide gain access to the highest-quality data possible.

“Reaching new records two years in a row shows that ALMA is not just maintaining excellence — it’s continuously improving,” said Sergio Martín, Head of ALMA’s Department of Science Operations. “What’s remarkable is that we achieved this during one of the toughest winters on the plateau in almost ten years. ALMA operates around the clock with a dedicated team keeping complex systems running safely and precisely, day and night. That’s how resilient and committed our team is.”

Indeed, ALMA’s operational efficiency is comparable to that of the most reliable infrastructures in the world, such as international airports and power plants that operate continuously under extreme conditions. During Cycle 11, ALMA observed for about 51% of the total year-round available time with the 12m-Array– despite a scheduled maintenance pause in February and several snowstorms during one of the harshest years in terms of climate.

This achievement reflects the coordinated effort of hundreds of professionals across the observatory and its partners in East Asia, Europe, and North America. Their dedication continues to drive ALMA’s mission to push the boundaries of human knowledge and reveal the hidden universe.

Additional Information

ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSTC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.

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