Picture of the Week

25 May 2015: In this image, taken by ESO Photo Ambassador Yuri Beletsky, the control building at the Paranal Observatory can be seen below a rising Milky Way, like the proverbial pot of gold at the end of a celestial rainbow. This building is a hub for the observatory’s operations, and it is from here that the Very Large Telescope (VLT), the VLT interferometer (VLTI), the VLT Survey Telescope (VST) and VLT Infrared Survey Telescope for Astronomy (VISTA) are controlled and maintained. The team of astronomers, telescope and instrument operators, and engineers is on site 24 hours a day to to run these telescopes and to keep them in top condition. The control building is located on a “shelf” below the main observing platform at the top of the Paranal Mountain. All functions of the four Unit Telescopes (UTs), the four Auxiliary Telescopes (ATs), the two survey telescopes are controlled from their own ...

18 May 2015: Shown here is the Atacama Large Millimeter/submillimeter Array (ALMA), located high on the Chajnantor Plateau in the Chilean Andes, 5000 metres above sea level. The rocky edge visible in the foreground of the image is a mountain that looms above ALMA. It is here that the 1-metre pathfinder telescope, called MiniTAO, is situated. MiniTAO is part of the University of Tokyo Atacama Observatory (TAO) project which will later see the construction of a larger 6.5-metre infrared optimised telescope on the site. NAOJ, ESO and the other partners involved in ALMA selected this site because it is one of the highest and driest astronomical observatory sites on Earth. ALMA is comprised of 66 high-precision antennas spread over a distance of up to 16 kilometres. The antennas use a technique known as interferometry to combine their signals, enabling them to act as a single giant antenna. Signals from each of the antennas ...

11 May 2015: This image shows ESO’s La Silla Observatory perched on the outskirts of the Chilean Atacama Desert and cloaked in an iridescent sky. Deep reddish hues permeate the right side of the frame and give way to the Milky Way, which can be seen with stunning clarity from La Silla, a location boasting some of the darkest and clearest night skies on Earth. The red and greenish-yellow glow is caused by airglow — a glow caused by the Earth’s atmosphere that is usually only seen from space, or at very dark locations. Hogging the limelight in this frame is the silver dish in the foreground — the Swedish–ESO Submillimetre Telescope (SEST). Although it was decommissioned in 2003 and is no longer in service SEST still provides a picturesque target for keen photographers as it reflects the bright lights and colours of the skies above. In the background of the image is ...

4 May 2015: Rather than showing spectacular objects, some of the most surprising images of the Universe instead focus on emptiness. This new image from the 2.2-metre MPG/ESO telescope shows dark tentacles swirling outwards from a dark, blank spot of space in the centre of the frame, particularly conspicuous against the dense peppering of bright gold and red stars across the rest of the image. This region is not a hole in the cosmos, or an empty patch of sky. The dark lanes are actually made up of thick, opaque dust lying between us and the packed star field behind it. This obscuring dust forms part of a dark molecular cloud, cold and dense areas where large quantities of dust and molecular gas mingle and block the visible light emitted by more distant stars. It is still unclear how these clouds form, but they are thought to be the very early stages of ...

27 April 2015: In this new image dusk reveals a stunning night sky over ESO’s Paranal Observatory, home to the Very Large Telescope (VLT) — the flagship facility for European ground-based astronomy. As the Sun sets on the site the Milky Way is shown in magnificent detail. Although it appears to the naked eye as a clouded haze across the sky, the Milky Way consists of 100–400 billion individual stars strung out along its 100 000 light-year extent. In this image the Milky Way is a backdrop to the Unit Telescope number 4, also known as Yepun. Yepun is Venus in the Mapuche language, the language of the indigenous people from the south of Chile. Yepun is one of four 8.2-metre telescopes that can be used together as one giant telescope, allowing astronomers to detect details up to 16 times finer than would be possible with the individual telescopes. Together, the VLT has ...

20 April 2015: In this romantic scene a bright, crimson sunset complements the colourful centre of the Milky Way and the zodiacal light above the platform of the Very Large Telescope (VLT) on Cerro Paranal. The pink regions scattered across the disc of our galaxy are regions where new stars are being born. On average the disc is about 1000 light-years tall and about 100 000 light-years in diameter. The setting Sun is just one of over 400 billion stars found in the Milky Way. Captured in this image is one of the Unit Telescopes (UTs, here UT1 also known as Antu) and three of the four Auxiliary Telescopes (ATs) which form part of the Very Large Telescope Interferometer (VLTI). To the left of the UT is a very faint meteor, and the red supergiant star Antares stands out above the ATs. Antares is found at the heart of the constellation of Scorpius ...

13 April 2015: At the end of the long, winding road in this image is the Atacama Large Millimeter/submillimeter Array (ALMA)’s Operational Support Facility (OSF). The OSF serves as a base camp for contractors and staff working at ALMA and its facilities are the centre of all scientific activities related to ALMA’s daily operation. Beyond the ALMA camp the white salt flat known as El Salar de Atacama is visible, the largest salt flat in Chile. Towards the horizon is the mountain known as Cerro Quimal, the highest mountain of the Cordillera de Domeyko, and nearby lies Pukará de Quitor (Fort of Quitor) — a pre-Columbian archaeological site. This photograph was taken from 4660 metres above sea level by photographer José Velásquez during a Sunday trek from Cerro de Macón towards the Array Operations Site (AOS). ALMA is the largest astronomical project in existence and is a truly global partnership between Europe, North ...

6 April 2015: This photo, courtesy of the National Astronomical Observatory of Japan (NAOJ), shows one of the 66 antennas which form the Atacama Large Millimeter/submillimeter Array (ALMA), located on the Chajnantor Plateau in the Chilean Andes. Above the antennas, stars appear to rain down on the site. The downpour of stars is the result of a long exposure capturing their trail across the sky as the Earth rotates. The plateau on which ALMA is located was actually chosen in part due to its dryness. Radio waves can easily penetrate the Earth’s atmosphere, but moisture in the air absorbs them and degrades the quality of the observations. So just as well that this is not real rain! ALMA is an international partnership between Europe, North America and East Asia in cooperation with the Republic of Chile.

30 March 2015: With all 66 of their backs turned to the constellation of Orion, the antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) sit high on their perch on the Chajnantor Plateau in the Chilean Andes. Illustrating nicely why this spot was chosen for the array is an impressively clear view of the Orion Nebula — otherwise known as Messier 42. It lies in the centre of the image, with the dazzling red of the star Betelgeuse, otherwise known as Alpha Orionis, off to the right. These are two of the most impressive sights in the night sky. Betelgeuse is a red supergiant and notable for being a likely candidate amongst the stars in our galaxy to become a supernova in the near future. Near future on a cosmic scale — a recent report suggests in around 100 000 years, which is a mere galactic blink. When this does happen, it will ...

23 March 2015: This image shows the dome of the Danish 1.54-metre telescope that has been in operation at La Silla Observatory since 1979. The telescope has been involved in several breakthrough astronomical observations including the discovery of merging neutron stars as the possible origin of gamma-ray bursts (eso0533) and finding an exoplanet only five times more massive than the Earth (eso0603). Above the telescope, our home galaxy the Milky Way stretches across the sky with the bright central bulge aligned with the dome of the telescope. In the background to the right you can spot the dome which once held the MarLy 1-metre telescope.. The telescope saw first light in 1996 and was decommissioned in 2009. Before the MarLy, this dome hosted the 40-centimetre Grand Prisme Objectif, a photographic astrograph. In front of the MarLy dome, the enclosure of the small Marseille 0.36-metre telecope is visible. Links Babak’s image archive at ESO ...

16 March 2015: This beautiful image taken at ESO's Paranal Observatory shows the four Auxiliary Telescopes of the Very Large Telescope (VLT) Array, set against an incredibly starry backdrop on Cerro Paranal in Chile. The Auxiliary Telescopes are each 1.8 metres in diameter and work with the four 8.2-metre diameter Unit Telescopes to make up the world's most advanced optical observatory. The telescopes work together to form the VLT Interferometer (VLTI), a giant interferometer which allows astronomers to see details up to 25 times finer than would be possible with the individual Unit Telescopes. Hanging over the site are the prominent Small and Large Magellanic Clouds, visible only in the southern sky. These two irregular dwarf galaxies are in the Local Group and so are companion galaxies to our own galaxy, the Milky Way. The image was taken by our Flickr friend John Colosimo who submitted it to the Your ESO Pictures Flickr ...

9 March 2015: Resembling a cross between the Bespin Cloud City and the ice planet Hoth from Star Wars: The Empire Strikes Back, here we see ESO’s La Silla Observatory blanketed in snow as the Sun sets. The characteristic domes of the La Silla telescopes are closed off to protect the instruments from the harsh environment and icy weather. Amongst the plethora of white, the MPG/ESO 2.2-metre telescope is particularly distinctive due to its silver dome. On a normal night, as darkness falls, the telescope domes will open and begin their nightly routine of observing the cosmos. Despite being located in a very dry area of the world, La Silla does occasionally experience some precipitation in the form of snow and a spattering of rain, as seen in this chilly picture taken by ESO Photo Ambassador Malte Tewes. However, although it does get cold in the Atacama Desert, where La Silla is located ...

2 March 2015: This image shows the bright centre and swirling arms of the spiral galaxy NGC 6300. NGC 6300 is located in a starry patch of sky in the southern constellation of Ara (The Altar) which contains a variety of intriguing deep-sky objects. NGC 6300 has beautiful pinwheeling arms connected by a straight bar that cuts through the middle of the galaxy. While it may look like a standard spiral galaxy in visible-light images like this one, it is actually a Seyfert II galaxy. Such galaxies have unusually luminous centres that emit very energetic radiation, meaning that they are often intensely bright in part of the spectrum either side of the visible. NGC 6300 is thought to contain a massive black hole at its heart some 300 000 times more massive than the Sun. This black hole is emitting high energy X-rays as it is fed by the material that is pulled ...

23 February 2015: This stunning panorama shows the Licancabur volcano, just left of centre, high on the Chajnantor Plateau near to the site of the Atacama Large Millimeter/submillimeter Array (ALMA). The spattering of white objects in the sky, though it could be mistaken for snow, is in fact stars. Licancabur stands some 5920 metres high, located on the border between Chile and Bolivia. The border between the two countries cuts across the northeastern slope of the volcano, meaning that the lower two thirds of this northeastern slope actually belong to Bolivia. The sweep of white in the foreground of this image is made up of tall, thin blades of hardened snow and ice. These icy needles, known as penitentes, are a natural phenomenon found in the region (potw1221). Not so natural is the glow to the left of the image emanating from the street lights of the small Chilean town, San Pedro de ...

16 February 2015: The transition from night to day is captured in this new photograph of ESO's La Silla Observatory. The Moon hangs low to the left of this image, diluted by the morning Sun. This image, taken by ESO Photo Ambassador Alexandre Santerne captures ESO's 3.6-metre telescope on the top right. The telescope, which is located 2400 metres above sea level and is here silhouetted by the shadows of dawn, was inaugurated in 1976. It currently operates with the HARPS spectrograph, the most prolific exoplanet hunting machine in the world. La Silla is ESO's first observatory. Inaugurated in 1969 it is located 600 kilometres north of Santiago at the edge of the Chilean Atacama Desert. La Silla was the largest astronomical observatory of its time, leading Europe to the front line of astronomical research. As illustrated in this image, the skies above La Silla provide crystal clear conditions for astronomical viewing with ...

9 February 2015: Step outside the control room of the Very Large Telescope (VLT) at night, and you will be greeted with a jaw-dropping sight. Thousands of stars cover the sky and the Milky Way stretches from one horizon to another. In this image, the dark lanes of the Milky Way are visible, dense clouds of dust and gas that block out the light from background stars. The varying colours of the surrounding visible stars result from their different ages and temperatures — young, hot stars are very blue-white in colour, whilst the older, cooler generation appear more orange or red. For the astronomers, a sight like this means that good data is on the way due to the lack of polluting moonlight. In order to help keep the sky as dark as possible, any lights within rooms not currently in use inside the control building are turned off and blackout blinds are ...

2 February 2015: This unique and spectacular image of ESO’s La Silla Observatory features a cloudless sky stained with red and green airglow and bejewelled with celestial objects. Amongst the celestial cast are the Small and Large Magellanic Clouds just to the right of centre, the rosy-red glow of various star-forming regions and the faint green streak of a meteor just to the left of the Milky Way. These striking heavenly regulars are eclipsed however by the presence of something far more elusive and much closer to home. The six panels below the main image magnify a series of extremely rare atmospheric phenomenon known as sprites. A few hours before daybreak — signalled by the spire of zodiacal light rising from the base of the Milky Way — a powerful thunderstorm appeared on the distant horizon, and the Earth’s upper atmosphere became a playground for these ephemeral events. Named after Shakespeare’s mischievous sprites ...

26 January 2015: In this new ESO image, nightfall raises the curtain on a theatrical display taking place in the cloudless skies over La Silla. In a scene humming with activity, the major players captured here are Comet Lovejoy, glowing green in the centre of the image; the Pleiades above and to the right; and the California Nebula, providing some contrast in the form of a red arc of gas directly to the right of Lovejoy. A meteor adds its own streak of light to the scene, seeming to plunge into the hazy pool of green light collecting along the horizon. The telescopes of La Silla provide an audience for this celestial performance, and a thin shroud of low altitude cloud clings to the plain below the observatory streaked by the Panamericana Highway. Comet Lovejoy’s long tail is being pushed away from the comet by the solar wind. Carbon compounds that have been ...

19 January 2015: This striking new image shows ESO’s Paranal Observatory in Chile soon after sunset. The last rays of the day create a spectacular orange haze as they pass through the dusty lower levels of the atmosphere, setting a perfect scene for this picture of the week. In this long exposure image we can see star trails caused by the movement of stars across the sky as the earth rotates. These tracks look a little like dotted lines, an effect caused by combining a number of individual shots taken with short gaps in between. The crookedness at the bottom of the star trails is due to the camera moving out of place. The path of the crescent Moon can also be seen towards the lower left of the frame as it slowly sets, appearing to sink into the Pacific Ocean. The moon is not trailed as it was taken with a series ...

12 January 2015: Coated in a layer of ashen dust and littered with heavy equipment vehicles, the peak of Cerro Armazones appears conspicuously flattened as efforts continue to craft a platform for the European Extremely Large Telescope (E-ELT). This shot of the monumental work in progress was taken from a quadcopter by ESO Photo Ambassador Gerd Hüdepohl, allowing a stretch of the Chilean Coastal Range, with Cerro Paranal and the Very Large Telescope, to be unveiled as a dramatic backdrop. The Atacama Desert and its crumpled mountains unfurl outwards, dissolving into a hazy blue towards the horizon. They provide a largely featureless but quietly arresting stage for the E-ELT, which will serve as the world’s largest optical and near-infrared telescope. The clear skies of the Atacama provide the E-ELT with the perfect conditions to see the Universe with a sharpness far exceeding even that of the NASA/ESA Hubble Space Telescope. When operational, this ...