VLT: then vs now

A lot can change in more than two decades — just take a look at these pictures of ESO’s Very Large Telescope (VLT)! On the left we see the VLT when it was still under construction atop Cerro Paranal in Chile, while on the right we see it in all its glory as it stands today. 

Before building the telescopes themselves the mountain had to be lowered by 28 metres to create the telescope platform, which meant removing some 350 000 cubic metres of rock. Then in 1998 the Unit Telescope UT1 (Antu), the leftmost telescope and the furthest along in its construction in the “then” picture, captured its first image of the cosmos — 25 years ago this week. Today, the VLT consists of four Unit Telescopes with main mirrors of 8.2 metres diameter and four movable 1.8-metre diameter Auxiliary Telescopes.

After a quarter of a century of observations, the VLT remains one of the world’s most advanced optical/infrared telescopes and is continuing to make key discoveries, and it’s being upgraded to help it pursue its mission to uncover the secrets of the Universe. These upgrades will ensure the VLT maintains its position at the forefront of science and engineering for years to come. 

Happy Birthday VLT!

Timeline

• 1991: construction began at Paranal
• 1996: the image on the left was taken
• 1998: UT1 first light
• 2022: the image on the right was taken