SEST at La Silla

The Swedish-ESO Submillimetre Telescope (SEST) reflects starlight from the sky above La Silla, ESO’s original observatory. Though now decommissioned, SEST was the only large sub-millimetre telescope in the southern hemisphere at the time of its first light, and helped pave the way for APEX and ALMA. During its operations, the instrument SIMBA was installed on it, measuring radio waves and allowing astronomers to study celestial objects including planet-forming discs around nearby stars, and distant galaxies of the early Universe. La Silla, which hosts several national telescopes, was inaugurated in 1969, and celebrates its 50th anniversary this year. It is situated at an altitude of 2400 metres in the outskirts of the Chilean Atacama Desert, where it enjoys more than 300 clear nights per year. It remains scientifically relevant among newer observatories; over 300 refereed publications per year are attributable to La Silla’s work, making it one of the most productive observatories in the world.