The ELT, step by step

The Extremely Large Telescope (ELT), is shown here under construction, including its dome, central structure and base of the M1 mirror. The ELT stands at Cerro Armazones in Chile's Atacama Desert and will be one of the main flagships of the European Southern Observatory for the next two decades. Thanks to on-site webcams, drone footage, and the contribution from professional and amateur photographers, ESO is able to share the development of the ELT with the world in real time, step by step.