Picture of the Week

12 October 2015: A pair of jets protrude outwards in near-perfect symmetry in this image of Herbig-Haro object (HH) 212, taken by ESO’s already decommissioned Infrared Spectrometer And Array Camera (ISAAC). The object lies in the constellation of Orion (The Hunter) in a dense molecular star-forming region, not far from the famous Horsehead Nebula. In regions like this, clouds of dust and gas collapse under the force of gravity, spinning faster and faster and becoming hotter and hotter until a young star ignites at the cloud’s centre. Any leftover material swirling around the newborn protostar comes together to form an accretion disc that will, under the right circumstances, eventually evolve to form the base material for the creation of planets, asteroids and comets. Although this process is still not fully understood, it is common that a protostar and its accretion disc, as seen here edge-on, are the cause of the jets in this ...

5 October 2015: This spectacular starry field of view shows the globular cluster NGC 6553 which is located approximately 19 000 light-years away in the constellation of Sagittarius. In this field, astronomers discovered a mysterious microlensing event. Microlensing is a form of gravitational lensing in which the light from a background source is bent by the gravitational field of a foreground object, creating an amplified image of the background object. The object causing the microlensing in NGC 6553 bent the light of a red giant star in the background (marked with an arrow). If this object lies in the cluster — something the scientists believe might only have a 50/50 chance of being correct — the object could be a black hole with a mass twice that of the Sun, making it the first of its kind to be discovered in a globular cluster. It would also be the oldest known stellar-mass black ...

28 September 2015: On the morning of Monday 28 September 2015 a spectacular total lunar eclipse was witnessed across Africa, the Americas, Europe and the Middle East. In Germany, it was photographed by Mahdi Zamani above the ESO Headquarters Extension and Technical Building. In this time-lapse sequence the Moon was visible between thin layers of cloud. It appeared bright to the upper-left and faded dramatically as it entered the Earth’s shadow and moved lower in the early morning sky. A lunar eclipse takes place when the Moon, Earth and Sun are exactly aligned. When the Moon passes through the shadow cast by the Earth, our planet blocks the path of direct sunlight to the lunar surface and a total eclipse occurs. This event can only happen on the night of a full Moon. This morning's total lunar eclipse took place during a supermoon — a full Moon which occurs at the same time ...

21 September 2015: This striking picture of the New Technology Telescope (NTT) was taken just after sunset at ESO's La Silla Observatory, located in the Norte Chico in outskirts of the Chilean Atacama Desert. The Moon has already begun its journey across the evening sky, and is shining brightly overhead. The Sun dips below the horizon to the left of the frame, soaking the clouds in a rich orange colour. The warm glow of the last rays of sunshine are caught by the reflective surface of the NTT walls. The purpose of this metallic dome is to stop the telescope’s enclosure from heating up during the day. This would affect the telescope’s observations, as rising warm air and turbulence blur images and worsen the astronomical seeing. It is not just the telescope's enclosure that is designed to reduce heat accumulation during the day; the concrete platforms and parking spaces around the site are ...

14 September 2015: The huge diffraction grating at the heart of the ultra-precise ESPRESSO spectrograph — the next generation in exoplanet detection technology — is pictured undergoing testing in the cleanroom at ESO Headquarters in Garching bei München, Germany. Engineers at ESO have recently completed the difficult process of aligning the grating. The production and alignment of this component is one of the key ESO contributions to the ESPRESSO project. The grating is the largest ever assembled at ESO, and its length matches the largest echelle grating ever made — the 1.2 x 0.3 metre grating for the HIRES spectrograph at the Keck 10-metre telescope. After its final alignment, the grating is fixed in a permanent mount. All its components are made of Zerodur (the same material that is used for the mirrors of the VLT) and will require no further adjustments, ever. This mounting technique was pioneered at ESO, and demonstrated to ...

7 September 2015: These images, taken two weeks apart, show the two hemispheres of Ceres and provide the best ground-based observations of the dwarf planet ever. They were taken using the SPHERE instrument on ESO's Very Large Telescope and form part of an effort undertaken since mid-July 2015 to compose a polarimetric map of the object's surface. Orbiting in the asteroid belt between Mars and Jupiter, a region known as the Main Belt, Ceres was the first asteroid to be discovered in 1801 and is the largest Main Belt asteroid. It is the largest reservoir of water in Earth's neighbourhood. Most of this water is thought to exist in the form of water ice in the object's mantle. The surface of the dwarf planet is about the size of India and several intriguing bright spots can be seen in these new images. These mysterious bright patches have also been looked at more closely ...

31 August 2015: This remarkable image was taken using a quadcopter, hovering high above the Atacama. Ocean, cloud and desert come together to form the aerial scene, stretching out along the Chilean coast. ESO’s Very Large Telescope (VLT) is softly illuminated by the Sun as it sets in the evening sky, throwing hues of orange and apricot across the observatory. On an adjacent peak towards the right of the frame, the 4.1-metre Visible and Infrared Survey Telescope for Astronomy (VISTA) stands apart, cutting a more solitary figure. The region in front of the VLT, filled with a lattice-like grid of rails, is used by the four small movable VLT Auxiliary Telescopes. Placing these telescopes at different distances apart adjusts the effective size of the VLT Interferometer, which acts as a single giant stargazer.

24 August 2015: This image, taken by ESO Photo Ambassador Alexandre Santerne, is more than a little disorientating at first glance! Resembling an optical illusion or an abstract painting, the starry circles arc around the south celestial pole, seen overhead at ESO's La Silla Observatory in Chile. Each circular streak represents an individual star, imaged over a long period of time to capture the motion of the stars across the sky caused by the Earth’s rotation. La Silla is based in the outskirts of Chile’s Atacama Desert at some 2400 metres above sea level, and offers perfect observing conditions for long-exposure shots like this; the site experiences over 300 clear nights a year! The site is host to many of ESO’s telescopes and to national projects run by the ESO Member States. Some of these telescopes can be seen towards the bottom of the image. The ESO 3.6-metre telescope stands tall on the ...

17 August 2015: In this panoramic image taken by Babak Tafreshi — a member of the ESO Ultra HD Expedition team — the ALMA Observatory’s antennas appear to take in the sight of the Milky Way, arching like a galactic rainbow of dust and stars over the Chajnantor Plateau in the Chilean Andes. Located 5000 metres above sea level, the Chajnantor Plateau serves as an ideal hunting ground for ALMA. The array uses observations at the millimetre and submillimetre wavelengths to explore the coldest parts of the Universe. The superb aridness of the plateau means that far less submillimetre radiation is absorbed and attenuated by water vapour than would be the case closer to sea level. As ALMA seeks to capture the secrets of the Universe, Babak Tafreshi and his fellow team members seek to capture the beauty and grandeur of ESO’s observatories and their unusual surroundings. Comprising four celebrated astrophotographers and ESO ...

10 August 2015: This view shows La Residencia, the hotel that provides an oasis for the astronomers and staff working at ESO’s Paranal Observatory in Chile. The image is taken from the south corner of the building, looking north towards the Very Large Telescope (VLT) sitting atop the summit of Cerro Paranal at some 2635 metres above sea level. The VLT is the flagship facility for European ground-based optical astronomy, and is the world’s most advanced optical observatory. The windows of the 108 rooms of La Residencia look west (left on the photo) towards the Pacific Ocean. Designed by the German architects Auer+Weber+Assoziierte, this award-winning building was featured as a backdrop for part of the James Bond film Quantum of Solace. It was built in a partially subterranean L-shape, making use of natural materials to allow it to blend in with the colours of the desert’s Mars-like landscape. It is little surprise that ...

3 August 2015: The bright star in the centre of this image is not the star of this show. At the bottom centre is a rather unremarkable smudge of red which is in fact a rare and valuable object. First discovered by amateur Japanese astronomer, Yukio Sakurai, in 1996, and noted as a nova-like object, Sakurai’s discovery turned out to be far more interesting than the supernova he initially supposed it to be. The object is actually a small white dwarf star undergoing a helium flash — one of only a handful of examples of such an event ever witnessed by astronomers. Normally, the white dwarf stage is the last in the life cycle of a low-mass star. In some cases, however, the star reignites in a helium flash and expands to return to a red giant state, ejecting huge amounts of gas and dust in the process, before once again shrinking to ...

27 July 2015: This photograph shows the road to the Atacama Large Millimeter/submillimeter Array (ALMA)’s Operations Support Facility (OSF) and then on further to the breathtaking Chajnantor Plateau at 5000 metres above sea level. The plateau, situated in Chilean Puna in the Atacama region, is home to the Array Operations Site (AOS) and is the site of the highest and driest astronomical observatory on Earth. The OSF is the centre of activities for the ALMA project and is where all staff and contractors are accommodated — only 2900 metres above sea level. This is where all the scientific operations related to the daily operation of the observatory take place. The AOS houses a technical building — the second highest building on Earth — along with the ALMA correlator, the highest and fastest computer ever used at an astronomical site. Due to the high altitude, human operations are kept to a minimum. ALMA will ...

20 July 2015: Here we see the now-obsolete Swedish–ESO Submillimetre Telescope (SEST), watching vigilantly over the horizon at ESO’s La Silla Observatory like a sentinel. Below, stratus clouds blanket the valley. SEST was installed at La Silla in 1987, and at the time of its first light was the only large submillimetre telescope operating in the southern hemisphere. Although it was decommissioned in 2003, the 15-metre diameter dish remains at La Silla Observatory and serves as a tribute to the groundbreaking work it accomplished — both as a standalone telescope, and also as a testbed for later projects such as the Atacama Pathfinder Experiment telescope (APEX) and the Atacama Large Millimeter/submillimeter Array (ALMA). During its tenure, SEST made several big discoveries, including, in 1995, finding the Boomerang Nebula to be the coldest place in the Universe at just one degree above absolute zero, and discovering the first extragalactic silicon monoxide maser. This beautiful ...

13 July 2015: Not all regions of Chile are as stark and barren as the ESO observing sites at Paranal, La Silla, and Chajnantor. ESO’s Santiago office, located in Vitacura, is sometimes visited by passing rainclouds and plays host to astronomers, technicians and administrative staff. Some 15 kilometres off in the background of this image, the beautiful snow-capped peaks of the Chilean Andes are visible. On a clear day the peaks can be viewed from almost anywhere in the city. They serve as a constant reminder of the natural boundaries of the busy city and its proximity to nature, should anyone require a break from the hustle and bustle of city life. Visitors to the area can take an easy hike in the Parque Natural Aguas de Ramón or fans of local flora and fauna may like to visit the Santuario de La Naturaleza El Arrayán (nature sanctuary), both located close to the ...

6 July 2015: This image by ESO Photo Ambassador Alexandre Santerne shows the Swedish–ESO Submillimetre Telescope (SEST) on the left, alongside the ESO 3.6-metre telescope on the right. In the background bright star trails circle the La Silla Observatory where the telescopes are situated, in the outskirts of the Atacama Desert in Chile. Star trails like these are created by using a long exposure to capture the apparent motion of the stars in the night sky as the Earth rotates. This image is a composite of 250 consecutive one-minute exposures, spanning four hours. A flipped version of the star trails is also visible as a reflection in the dish of the telescope. The reflection also includes the red lights of a car passing by. La Silla is ESO’s first observatory and has been a major ESO stronghold since the 1960s. SEST was, at the time of construction, the only large submillimetre telescope in ...

29 June 2015: On 27 June 2015, the ESO Headquarters in Garching, Germany, opened its doors to the public as part of the Long Night of Science (Lange Nacht der Wissenschaften), along with the other facilities based at the science campus in Garching. ESO invited visitors to experience the work of this world-leading ground-based astronomy organisation at first hand with eighteen different activities to take part in. In the picture ESO astronomer Vinod Arumugam is making a comet out of dry ice. Before the doors had even opened at six in the evening people were waiting outside, eager to look around the Headquarters and take part in the activities within. In total, 3800 people attended the events and had 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; visit the exhibition LIGHT: ...

22 June 2015: 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. ...

15 June 2015: ESO’s Paranal Observatory is one of the best places on Earth to take in the night sky. This panorama of ESO’s Very Large Telescope (VLT) atop the platform of Chile’s Cerro Paranal was taken by Babak Tafreshi, one of the ESO Photo Ambassadors. A mix of colours sweeps across the sky in this image. From the fiery red sunset up to the dusty purple band of the Milky Way. Although the VLT site is one of the best places on Earth for astronomy, the telescope must still overcome the natural distortions caused by our atmosphere. This is done through a process known as adaptive optics. Astronomers can make use of an artificial star by shining a powerful laser — seen here projected from the telescope on the far right — to correct for the blurring caused by the atmosphere. The VLT, as a flagship facility for European astronomy, has opened ...

8 June 2015: The Crab Nebula, which also goes by the names Messier 1, NGC 1952 and Taurus A, is one of the best studied astronomical objects in the sky. It is the remnant of a supernova explosion which was observed by Chinese astronomers in 1054. The tangled filaments visible in this image are the remains of the exploded star, which are still expanding outwards at about 1500 kilometres per second. Although not visible to the naked eye due to foreground filaments of helium and hydrogen the heart of the nebula hosts two faint stars. It is one of these that is responsible for the nebula that we see today — a star that is known as the Crab Pulsar, or CM Tau. This is the small, dense, corpse of the original star that caused the supernova. It is now only about 20 kilometres in diameter and rotates around its axis 30 times ...

1 June 2015: The brilliant starry sky, the red sand and the ice structures piercing the foreground of this image combine to give the impression of a desert far from the reach of human footprints. A landscape that could easily be mistaken for the polar regions of our distant neighbour Mars. The jagged tooth-like formations are not on the Red Planet however, but on the sloping hills of the Atacama Desert. The formations are called penitentes — structures made of snow and ice that form mostly at high altitudes. The low pressure, moisture and temperature at these altitudes help to create this interesting and rare behaviour in the freezing of ice. The strange structures also have a tendency to orient themselves towards the Sun, which is why they are all perfectly aligned like a carefully tended garden of ice. As if this beautiful quirk of nature wasn’t enough, above the structures lies an ...