Yepun and the Milky Way

Illuminated by the stars of the Milky Way, the majestic fourth Unit Telescope (UT4) of the Very Large Telescope (VLT) sits atop Cerro Paranal, ready to observe the night sky.

The Paranal Observatory, at an altitude of 2635 metres above sea level, is the world”s most advanced ground-based astronomical observatory and ESO’s flagship facility.

UT4 — also known as Yepun (Venus) — has a main mirror 8.2 metres diameter, and is one of four Unit Telescopes that comprise the VLT. The others are known as Antu (Sun), Kueyen (Moon) and Melipal (Southern Cross). The names of the telescopes are words from the language of the Mapuche people who live some 500 kilometres south of Santiago de Chile.

The four Unit Telescopes can work together to form the ESO Very Large Telescope Interferometer (VLTI). The VLTI allows astronomers to measure details up to 16 times finer than with the individual telescopes.

Visible slightly above the plane of the Milky Way and at the heart of Scorpius (The Scorpion) is the bright red star Antares, the sixteenth brightest star in the night sky. Almost all other objects and constellations are impossible to pick out in this sea of stars.

This picture was taken by photographer John Colosimo with an exposure time of 30 seconds, during which the rotation of the Earth caused the stars to appear as little trails.