Extremely Large Telescope Rotates for the First Time in Major Milestone

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ESO's Extremely Large Telescope shows off its impressive size after reaching a new milestone. (Image credit: ESO/Cimolai) The Extremely Large Telescope just passed a serious milestone while coming together. But it's not done yet; the immense telescope is about to get even larger.

What is it?

The European Organization for Astronomical Research in the Southern Hemisphere (ESO)'s Extremely Large Telescope is under construction on a mountaintop in Chile.

In this new photo , we can really get an idea of the telescope's size. The snapshot was captured during a milestone moment for the crew working on the observatory. They rotated the telescope's structure around its vertical axis for the first time.

This wasn't just an exercise for the dedicated crew working on the ELT, but rather an important test. The team needed to ensure this rotational motion works smoothly to confirm it's possible to point the telescope at any area of the night sky .

Why is it incredible?

This rotation was no small feat with a telescope weighing about 7.7 million pounds (3,500 metric tons), and we can see some of the crew who made it happen posing with their handiwork. They had to first rotate the telescope by hand just centimeters at a time. This push led to auxiliary motors taking over to complete the full rotation.

At its current size, the ELT is enormous. But it will actually get bigger and heavier. Later on in the process, mirrors and science instruments will be installed, skyrocketing the telescope to over 10 million pounds (4,600 metric tons).

"For me, this is a beautiful reminder of what can be achieved when people push in the same direction, literally and figuratively,” Roberto Tamai, the ELT’s Program Manager at ESO, shown on the right in this image, said in a statement .

Tamai is shown standing next to Marco Sciarra, Executive President of Cimolai (a company working on the telescope's construction), in the middle and Pascal Martinez, ESO's Project Manager for the Dome and Main Structure of the ELT, on the left.