Picture of the Week

29 December 2014: Here we see a swirling starscape above ESO’s La Silla Observatory. A long series of individual images have been combined to form this striking shot, allowing the motion of the Earth to be captured as it rotates, with stars producing long trails around the sky’s south pole as it does so. The familiar silver dome of the MPG/ESO 2.2-metre telescope is seen in the foreground. Moving into the shot, we next see the white dome of the ESO 1-metre Schmidt telescope, the rectangular building of the New Technology Telescope, and at the back, the double domes of the ESO 3.6-metre telescope with its adjacent smaller sibling, the now-decommissioned Coudé Auxiliary Telescope. But what are those streaks in the sky? Is it a bird? Is it a plane? Well, yes, it is indeed a plane. In fact, if you look very closely, you can see not one, but three horizontal trails ...

22 December 2014: Season’s Greetings on behalf of everyone at the European Southern Observatory! We wish you happy holidays, a good start into the next year and a fruitful 2015! Links: Christmas card 2014

15 December 2014: Rainbows are widely appreciated for the welcome touch of colour they can bring to an otherwise dark and dreary day, and this rainbow is no exception. This rare rainbow appears over the Atacama Large Millimeter/submillimeter Array (ALMA) Operations Support Facility (OSF), which lies some 2900 metres above sea level close to San Pedro de Atacama. The OSF is the base camp for the ALMA site, which is significantly higher at over 5000 metres up on the Chajnantor Plateau. The OSF isn’t just a location for operating the giant ALMA Observatory; it is also where new technologies are assembled, integrated, and verified before they are transported to their final destination on Chajnantor. The technology has to be assembled and tested at the OSF because the air is much denser there than on the plateau, and workers can complete their tasks without the adverse health risks associated with working at high altitude. ...

8 December 2014: La Silla sits at the lowest height above sea level of all ESO’s observatories in Chile. At 2400 metres, it is around 200 metres lower than Paranal and sits at half the altitude of ALMA, which resides on top of Chajnantor at an ear-popping 5000 metres above sea level. Despite being the lowest observatory in terms of elevation, scientists at La Silla are still reminded of the extreme altitude when they step outside and see spectacles like this one — clouds just beneath their feet! As La Silla is in the Southern outskirts of the Atacama Desert, one of the driest places on Earth, it may come as a surprise to see cloud formations in the region, but this arid climate is the result of the Peruvian Humboldt Current. This current is caused by the upward movement of cold water from the depths of the nearby Pacific Ocean, and flows ...

1 December 2014: This image shows a region of the Milky Way that lies within the constellation of Scorpius, close to the central plane of the galaxy. The region hosts a dense cloud of dust and gas associated with the molecular cloud IRAS 16562-3959, clearly visible as an orange smudge among the rich pool of stars at the centre of the image. Clouds like these are breeding grounds for new stars. In the centre of this cloud the bright object known as G345.4938+01.4677 can just be seen beyond the veil of gas and dust. This is a very young star in the process of forming as the cloud collapses under gravity. The young star is very bright and heavy — roughly 15 times more massive than the Sun — and featured in a recent Atacama Large Millimeter/submillimeter Array (ALMA) result. The team of astronomers made surprising discoveries within G345.4938+01.4677 — there is a ...

24 November 2014: Studying red giant stars tells astronomers about the future of the Sun — and about how previous generations of stars spread the elements needed for life across the Universe. One of the most famous red giants in the sky is called Mira A, part of the binary system Mira which lies about 400 light-years from Earth. In this image ALMA reveals Mira’s secret life. Mira A is an old star, already starting to throw out the products of its life’s work into space for recycling. Mira A’s companion, known as Mira B, orbits it at twice the distance from the Sun to Neptune. Mira A is known to have a slow wind which gently moulds the surrounding material. ALMA has now confirmed that Mira’s companion is a very different kind of star, with a very different wind. Mira B is a hot, dense white dwarf with a fierce and fast ...

17 November 2014: Have you ever wondered what the inside of ESO's Very Large Telescope looks like? Well, wonder no more, as this picture of the week shows the internal structure of one of the VLT's Unit Telescopes (UTs) — specifically UT3, otherwise known as Melipal. Seen here, lit by moonlight, is the main steel structure of the Unit Telescope's optical assembly. The main mirror, measuring 8.2 metres in diameter and weighing in at more than 23 tonnes, requires a sturdy frame to allow it to rotate within the structure, while maintaining high optical resolution. This movable steel frame itself weighs over 430 tonnes, about the same as a fully loaded jumbo jet! The structure, optics and electronics are housed within a further steel enclosure, which provides protection from the harsh Atacama environment. Melipal is named after the Mapuche term for the constellation of the Southern Cross. All four of the VLT's Unit ...

10 November 2014: This week removal of the temporary office buildings at the ESO Headquarters in Garching, Germany began. This image shows them being dismantled, and captures both the beginning, and end, of an era. The ESO staff members who had been working in the temporary buildings — seen here in this aerial photo taken earlier this year — moved into the new Headquarters extension at the beginning of this year. The removal of the containers marks the end of this transition period. It also marks the beginning of the construction of the ESO Supernova Planetarium & Visitor Centre. In a few months, on the site once occupied by the temporary office buildings, the construction of ESO’s newest building will begin. The ESO Supernova is scheduled to open in spring 2018 and will offer its visitors a modern, interactive astronomical exhibition and one of the most advanced planetariums in the world. The removal ...

3 November 2014: The smokey black silhouette in this new image is part of a large, sparse cloud of partially ionised hydrogen — an HII region — known as Gum 15. In wide-field images this nebula appears as a striking reddish purple clump dotted with stars and slashed by opaque, weaving dust lanes. This image homes in on one of these dust lanes, showing the central region of the nebula. These dark chunks of sky have seemingly few stars because lanes of dusty material are obscuring the bright, glowing regions of gas beyond. The occasional stars that do show up in these patches are actually between us and Gum 15, but create the illusion that we are peering through a window out onto the more distant sky. Gum 15 is shaped by the aggressive winds flowing from the stars within and around it. The cloud is located near to several large associations of ...

27 October 2014: A solitary laser beam cuts through the night sky. It streaks upwards from Unit Telescope 4 of ESO's Very Large Telescope, located at Paranal Observatory in Chile. The two Magellanic Clouds are visible to the left of the beam as faint, fuzzy patches against the starry background. The particularly bright star to the right of the beam is Canopus, the second brightest star in our night sky after Sirius. When ground-based telescopes view stars, the light they collect must travel through the layers of our atmosphere. The same water vapour, pollution, and turbulence that causes the stars in the sky to twinkle also result in blurred images — so in comes a technique known as adaptive optics. Adaptive optics systems use sophisticated deformable mirrors to counteract the negative effects of our atmosphere. The laser shines up into the sky, creating an artificial star about 90 kilometres from the ground. Astronomers ...

20 October 2014: This photograph from the ESO Open House Day 2014 shows children and adults listening to the adventures of Space Rock Pedro. This was one of the sixteen activities available when ESO Headquarters in Garching, Germany, opened its doors to the public on 11 October 2014. In conjunction with the other facilities based at the science campus in Garching, ESO invited visitors to experience at first hand the work of the world-leading ground-based astronomy organisation. Before the doors had even opened at 11:00 people were waiting outside, eager to look around the new headquarters and experience all the main activities available. In total, 3300 people took the chance to have their questions answered by experienced astronomers; see live experiments; join guided tours through the new office and technical buildings; listen to talks about ongoing astronomical research; and even participate in live interviews with astronomers in the Chilean Atacama Desert. Also included ...

13 October 2014: This colourful picture resembles an abstract painting, or perhaps a contemporary stained-glass window. But it is actually an unusual view of a galaxy taken with the new MUSE instrument on ESO’s Very Large Telescope. Colours in astronomical pictures are usually related to the real colour of an object. In this image, however, the colours represent the motion of the stars that form the giant elliptical galaxy Messier 87 — one of the brightest galaxies in the Virgo Cluster which lies about 50 million light-years away. Red in the image indicates that stars in that part of the object are, on average, moving away from us, blue means they are coming towards us, and yellow and green are in between. This new map of Messier 87 from MUSE shows these trends more clearly than ever before. It reveals a slow rotation of this massive object — the upper left part (in ...

6 October 2014: This aerial image shows a 1:1 scale model of the European Extremely Large Telescope's primary mirror, assembled next to the Asiago Astrophysical Observatory near Asiago, Italy. The Italian observatory, founded in 1942, is dwarfed by the gargantuan E-ELT mirror… in fact, you could fit the entire Asiago building inside the footprint of the E-ELT mirror and still have enough room to swing a proverbial cat (and a big cat too)! Around the edge of the mock-up mirror are the children who volunteered to participate in the task of positioning the 800 1.4-metre cardboard hexagons used to form the 39-metre E-ELT mirror mock-up.

29 September 2014: Sitting atop Cerro Paranal high above the Atacama Desert in Chile, two of the Very Large Telescope's Unit Telescopes quietly bask in the starlight, observing the Milky Way as it arches over ESO's Paranal Observatory. Several interesting objects can be seen in this picture. Some of the most prominent are the two Magellanic Clouds — one Small (SMC), one Large (LMC) — which appear brightly in between the two telescopes. By contrast, the dark Coalsack Nebula can be seen as an obscuring smudge across the Milky Way, resembling a giant cosmic thumbprint above the telescope on the left. The Magellanic Clouds are both located within the Local Group of galaxies that includes our galaxy, the Milky Way. The LMC lies at a distance of 163 000 light-years from our galaxy, and the SMC at 200 000 light-years. The Coalsack Nebula, on the other hand, is a mere stone's throw away ...

22 September 2014: The 15-metre diameter Swedish–ESO Submillimetre Telescope (SEST) was built in 1987, and was operated at ESO's La Silla Observatory in Chile until it was decommissioned in 2003. At the time of construction, SEST was the only radio telescope in the southern hemisphere that was designed to observe the submillimetre Universe, and it paved the way for later telescopes such as the Atacama Pathfinder Experiment telescope (APEX), and the Atacama Large Millimeter/submillimeter Array (ALMA), both located at Chajnantor. In this image, we see a crowded night sky filled with star trails, a result of the camera's long exposure time. The starlight is reflected back at numerous different angles towards the camera from the giant parabolic dish. In the background, the ESO 3.6-metre telescope stands in its dome, silently surveying the cosmos. This dizzying picture of the SEST telescope at La Silla was taken by ESO Photo Ambassador José Joaquín Pérez. Links ...

15 September 2014: Here we see ESO's La Silla Observatory with a backdrop of the Milky Way. Established in the 1960s, La Silla was ESO's first observatory to be built in Chile. Visible on the hill in the centre of this image is the rectangular New Technology Telescope (NTT) on the left, and the domed ESO 3.6-metre telescope to the right. The 3.58-metre NTT was inaugurated in 1989, and was the first in the world to have a computer-controlled main mirror. The main mirror is flexible, and its shape is actively adjusted during observations to preserve the optimal image quality. This technology, known as active optics, is now applied to all major modern telescopes — including the Very Large Telescope at Cerro Paranal, and the future European Extremely Large Telescope. La Silla is home to several other telescopes, including the Swedish–ESO Submillimetre Telescope (SEST), and the robotic TAROT, which is used to monitor ...

8 September 2014: The bright, hazy smudge at the centre of this image is a comet known as 67P/Churyumov-Gerasimenko, or 67P/C-G for short. This is not just any comet; it is the target for ESA’s Rosetta spacecraft, which is currently deep within the comet’s coma and less than 100 kilometres from its nucleus [1]. With Rosetta so close to the comet, the only way to view the whole of 67P/C-G now is to observe it from the ground. This image was taken on 11 August 2014 using one of the 8-metre telescopes of ESO’s Very Large Telescope (VLT) in Chile. It was composed by superimposing 40 individual exposures, each lasting 50 seconds, and removing background stars, to obtain the optimal view of the comet. Rosetta is contained within the central pixel of this image, and is too small to resolve. The VLT is made up of four individual Unit Telescopes that can work ...

1 September 2014: This groovy and psychedelic photograph shows a night of observing the Northern Celestial Pole from the Allgäu Public Observatory in Ottobeuren, Germany. Pictured here is the facility's 0.6-metre Cassegrain reflector telescope, which was installed in 1996. The brilliant yellow laser beam, which appears to fan out across the sky in this long-exposure image, is ESO's Wendelstein laser guide star unit which was tested at the site in Allgäu. It is a precursor, experimental version of the fibre laser that has been installed on the Very Large Telescope in Paranal, Chile. A Laser guide star is used to create a bright spot in the sky, which can be used as an artificial reference star, allowing astronomers to measure how the real stars blur or twinkle, as normally seen from the ground. The measurements are then used to correct this blurring and enable sharper images to be taken, in a process is ...

25 August 2014: In the Atacama Desert in Chile, it rarely rains. Only once every few years does significant rain or snow precipitate on ESO’s La Silla Observatory, generally coinciding with an anomalously warm weather event such as an El Niño event. This desert is one of the driest places on Earth, making it a fantastic site from which to observe the night sky. Although there may be very little real rain, some photography tricks can instead make the stars appear to rain onto the surrounding mountains, as seen in this image taken on 21 May 2013 by Diana Juncher, a PhD student in astronomy at the Niels Bohr Institute, Denmark. Diana was at La Silla for two weeks in May 2013, observing exoplanets towards the centre of our galaxy as part of her research. During her stay she managed to take this image of star trails, taken only around 20 metres away ...

18 August 2014: A rare patch of wispy white clouds streak across the sky over ESO’s La Silla Observatory in this photograph, taken on 11 June 2012 by astronomer Alan Fitzsimmons. This dry, desolate environment with occasional strong gusts of wind may not be the best place for people to set up home, but it is the ideal location for telescopes. Dry, arid conditions help astronomers to avoid common observing problems like atmospheric disturbance, light pollution, humidity, and (most of the time!) clouds, allowing them to gain a clearer view of the cosmos above. Even on this rare day of cloud the sky had cleared by nightfall and observations took place as usual. The telescopes that call La Silla home — including two major ESO-operated telescopes: the ESO 3.6-metre telescope and the New Technology Telescope (NTT) — are equipped with state of the art instruments, enabling them to fully exploit the unique viewing ...