Sunrise silhouettes the world’s largest telescope | Space photo of the day for Sept. 17, 2025

Deep in the Chilean desert, the European Extremely Large Telescope (ELT) is currently under construction. Operated by the European Southern Observatory (ESO), the ELT’s design features a 128-foot-wide (39 meters) primary mirror, making it the largest optical and infrared telescope in the world when completed.

In this image, cranes flank the rising solar disk with Earth still in shadow as the first light silhouettes humanity’s next giant eye on the sky.

What is it?

The ELT is one of the most ambitious ongoing projects in astronomy, with a cost of 1.3 billion euros (around $1.4 billion US). Construction is underway atop Cerro Armazones, a mountaintop in Chile’s Atacama Desert. Here, the lack of light pollution and moisture will allow the telescope to take more accurate readings of deep space and its structures.

Where is it?

This photograph was taken at Cerro Armazones in Chile, at an elevation of 10,052 feet (3,064 m) above sea level.

Why is it amazing?

The ELT’s size and advanced instrumentation will let astronomers see fainter and more distant objects than ever before. The giant scope will image exoplanets in reflected light, explore the earliest galaxies formed after the Big Bang and much more.

As the sun rises behind the ELT, the image stands for the dawning of a new era in astronomical discovery. When operational, the ELT will help us observe light from the most ancient parts of the universe.

Want to learn more?

You can read more about astronomy and telescopes in Chile.