Officials building a huge telescope atop Cerro Armazones in Chile’s Atacama Desert have celebrated the mid-point towards completion.

The Extremely Large Telescope (ELT), built by the European Southern Observatory (ESO), will, once complete in 2028, be the largest telescope in the world for visible and infrared light.

It includes a 39 m main mirror – made up of 798 hexagonal segments  – as well as four smaller mirrors. Engineers and construction workers are currently assembling the structure of the telescope dome while the telescope mirrors are being built by companies in Europe.

“Reaching 50% completion is no small feat, given the challenges inherent to large, complex projects, and it was only possible thanks to the commitment of everyone at ESO, the continued support of the ESO member states and the engagement of our partners in industry and instrument consortia,“ notes ESO director general Xavier Barcons.

Construction of the ELT began in 2014 when the top of Cerro Armazones was flattened to allow the space for the giant telescope. Yet officials are confident that completing the remaining 50% will be much quicker than the first half, which was affected by the COVID-19 pandemic.