The entire arc of the Milky Way, full of gas, dust, star clusters and emission nebulae, makes a luminous background for the ESO-operated Very Large Telescope (VLT). The VLT is based at the Cerro Paranal site in the Atacama Desert of northern Chile, and it houses four 8.2-meter Unit Telescopes known as Antu, Kueyen, Melipal and Yepun, shown here lined up in front of a stunning starry backdrop. #

The Atacama Large Millimeter/submillimeter Array (ALMA) — comprises 66 high-precision antennae, spread over distances of up to 16 kilometers. The ability to reposition the antennae is part of what makes ALMA such a powerful telescope. Each state-of-the-art component weighs in at over 100 tons, yet despite their bulk they require incredibly precise positioning. That is where the ALMA transporters, fondly named Otto and Lore, come in. These bright yellow behemoths are able to position the antennas to within a few millimeters, ensuring accurate placement on the antenna foundation pads. #

On April 26, 2016 an event at ESO’s Paranal Observatory in Chile marked the brilliant first light for the four powerful lasers that form a crucial part of the adaptive optics systems on ESO’s Very Large Telescope. Attendees were treated to a spectacular display of cutting-edge laser technology against the majestic skies of Paranal. These are the most powerful laser guide stars ever used for astronomy and mark the first use of multiple laser guide stars at ESO. This spectacular image shows the four beams emerging from the new laser system on Unit Telescope 4 of the VLT. #

ESO's Paranal Residencia, the award-winning accommodation for those who come to use the telescopes at Paranal Observatory, emerges from the Chilean desert. The Very Large Telescope (VLT) sits atop the highest peak in the background. #

The Residencia hotel—also seen in the James Bond movie "Quantum of Solace"—in the middle of the Atacama desert, acts as an oasis of life in this hostile environment. It hosts the observing astronomers of the Paranal Observatory and gives them a place to sleep and to relax. One of the most loved spaces by the astronomers is the huge indoor garden, which also has a swimming pool. However, the pool is not only there for fun: The water also provides the otherwise completely dry air some humidity. This helps the plants in the garden to grow and prevents the eyes and lips of the astronomers to dry out. #

A graceful fox looks into the photographer's camera at the ALMA Antenna Operations Site, about 5,000 meters above sea level, in the Chajnantor plateau, Chile. Several of ALMA's antennas are visible in the background. The Andean foxes are a common sight at all ESO observatories. #

This long time exposure shows star trails at the La Silla observatory. The light of the stars is also reflected on the dish of the Swedish-ESO Submilimeter Telescope SEST. #

The Cat’s Paw and Lobster Nebulae. This spectacular image from the VLT Survey Telescope shows the Cat’s Paw Nebula (upper right) and the Lobster Nebula (lower left). These dramatic objects are regions of active star formation where the hot young stars are causing the surrounding hydrogen gas to glow red. The very rich field of view also includes dark clouds of dust. With around two billion pixels this is one of the largest images ever released by ESO. Note that the circular features in the image around bright stars are not real, they are due to reflections within the optics of the telescope and camera. #

The VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile captured this beautifully detailed image of the galaxy Messier 33, often called the Triangulum Galaxy. This nearby spiral, the second closest large galaxy to our own galaxy, the Milky Way, is packed with bright star clusters, and clouds of gas and dust. This picture is among the most detailed wide-field views of this object ever taken and shows the many glowing red gas clouds in the spiral arms with particular clarity. #

An aerial view of Cerro Armazones, the future home of the new E-ELT, taken on January 20, 2015. Despite its dusty and pale leveled peak, the mountain casts a commanding shadow over the desert. #

First imaged in 1989, red sprites are a ghostly phenomenon that occur at high altitudes above thunderstorms. Photographed here by ESO Photo Ambassador Petr Horálek, the unmistakable tendrils of multiple red sprites are spotted approximately 600 kilometers away from ESO's Paranal Observatory above distant thunderclouds. To capture multiple sprites, numerous exposures were combined to create this image. In the foreground sits a lone 1.8-meter Auxiliary Telescope, part of ESO's Very Large Telescope (VLT). #

This image shows penitentes, snow formations found at high altitudes. They take the form of tall thin blades of hardened snow or ice, closely spaced with the blades oriented towards the general direction of the Sun. #

The dynamism of ESO's Very Large Telescope in operation is captured in this unusual photograph, taken inside Unit Telescope 4. As the system swings into action, the rotating walls of the dome move around the telescope structure, seen stationary in the center of the image, which houses a mirror 8.2 meters in diameter. The movement of the dome is captured by an extended exposure time. #

ALMA Control Room, AOS Console. Antennae Array correlations by (left to right) Mareki Honma (Astronomer; Japan); Vasco Cortez (Engineer, Array operator; Chile); Adele Plunkett (Astronomer; US); and Rainer Mauersberger (Astronomer; ESO, Germany). #

This is the deformable secondary mirror (DSM), one of the key systems of the VLT Adaptive Optics Facility (AOF) in Paranal, Chile. The 1170 recesses for magnets surrounded by the chemically deposited rings of silver coating can be clearly seen. In this image the mirror is still undergoing optical tests. #

While the ESO observatories are quite busy during the dark hours of the night, during the day they are very quiet. To make sure astronomers are relaxed for the next observation night, signs remind visitors to be quiet. #

The biggest obstacle in ground based astronomy is the same thing that causes the stars to twinkle — the atmosphere. This effect is due to the distortion of light as it travels through turbulent gases to reach the Earth's surface. This stunning image, taken from a distance, shows the scientific solution — the 4 Laser Guide Star Facility on ESO's Very Large Telescope (VLT). The lasers form an integral part of the adaptive optics system on the VLT, by beaming artificial stars into the sky. Astronomers can then use these guide laser stars as reference points, allowing them to correct their observations of true celestial bodies. #

The Atacama Large Millimeter Array (ALMA) is situated more than 5,000 meters above sea level in the Chilean desert, on the Chajnantor plateau. Here, one of the telescope's 66 antennas is being worked on by specialist engineers. #

The intricate network of pipes surrounding the 24 spectrographs of the MUSE instrument on the VLT. The instruments complexity is equaled by its power and productivity. #