The world’s most advanced optical instrument has just turned 15, and the European Southern Observatory – made up of 15 European nations – has celebrated with the release of new images taken by the Very Large Telescope (VLT) from its home on the Paranal mountains of Chile.

The telescope originally opened as four large 8.2 metre Unit Telescopes on 25 May 1998, which have since been joined by four small Auxillary Telescopes.

The main VLT telescopes are primarily operated as four independent telescopes that can resolve objects four billion times fainter than what can be seen with the unaided eye, but around 20% of observations use a combination that provide details up to 25 times finer than with the individual telescopes alone. The light beams from each are then combined in the VLTI using a complex system of precisely aligned mirrors in underground tunnels.

Over its 15 years, the VLT has been credited with numerous astronomical firsts, including the first image of an extrasolar planet, tracking individual stars moving around the supermassive black hole at the centre of the Milky Way, and observing the afterglow of the furthest known Gamma-Ray Burst.

In 2012 alone, more than 600 refereed scientific papers were published based on data from the telescope – so even though the VLT will be joined soon by another, larger ESO instrument in Chile, the Extremely Large Telescope, its place as a leader in the provision of astronomical data will no doubt continue for years to come.