(Image: ESO)

This is a very special delivery. The last of the 66 enormous antennas that will complete the Atacama Large Millimeter Array (ALMA) observatory has arrived. Its new home is ALMA’s high-altitude site, 5000 metres above sea level on the Chajnator plateau.

The plateau’s dry and rarefied air is perfect for crystal-clear observations, but it’s a difficult place to work. That’s why the antennas are assembled and tested at a lower site – a mere 2900 metres up – and then moved via a 28-wheel transporter, visible here underneath the 12-metre dish.

The 66 dishes will soon work together as one massive telescope.

Even before all of its antennas were in place, ALMA had surpassed the capabilities of all other such arrays, despite being put out of service last year when workers went on strike, demanding compensation for the extreme working conditions.