The NTT stands guard

Back in 1989, the Sky & Telescope magazine announced “The Best Telescope Yet”. More than three decades later, the 3.58-metre New Technology Telescope (NTT) is still an active member of ESO’s telescope family at La Silla Observatory. In this Picture of the Week, the NTT’s distinctive shiny armor stands guard over the barren landscape of the Chilean Atacama Desert. Many of its technological developments were, in fact, breakthroughs that would later be used for ESO’s Very Large Telescope (VLT) and for the future ESO’s Extremely Large Telescope. 

The NTT's main breakthrough was its active optics system. Telescope mirrors may look perfectly smooth to our eyes, but changes in temperature, wind pressure or the weight of the mirror itself may deform them. But the NTT’s mirror was different: it was mounted on top of a supporting mechanism that corrected these deformations during the observations while monitoring a reference star. This allowed the NTT to obtain images about three times sharper than the ESO 3.6-metre telescope also at La Silla, despite being the same size. 

The NTT has helped uncover many secrets of the cosmos. It played a key role in the discovery of a supermassive black hole at the centre of our Galaxy. More recently, it witnessed a star being devoured by a black hole in another galaxy, among many other discoveries. The NTT still stands today as a testament of the ongoing technological advances in astronomical research.