Picture of the Week

17 September 2018: This image shows a dwarf galaxy in the southern constellation of Phoenix named, for obvious reasons, the Phoenix Dwarf. The Phoenix Dwarf is unique in that it cannot be classified according to the usual scheme for dwarf galaxies; while its shape would label it as a spheroidal dwarf galaxy — which do not contain enough gas to form new stars — studies have shown the galaxy to have an associated cloud of gas nearby, hinting at recent star formation, and a population of young stars. The gas cloud does not lie within the galaxy itself, but is still gravitationally bound to it — meaning that it will eventually fall back into the galaxy over time. Since the cloud is close by, it’s likely that the process that flung it outwards it is still ongoing. After studying the shape of the gas cloud, astronomers suspect the most likely cause of the ...

10 September 2018: From the 5 to 19 August this year, AstroCamp 2018 took place at the Centre for Environmental Education and Interpretation of the Corno de Bico Protected Landscape in northern Portugal. AstroCamp is an astronomy-focused summer academic program for secondary students, which aims to bring together students who have different backgrounds and life experiences, but a common passion: astronomy. Over the course of two weeks, the students — astronomy enthusiasts aged between 15 and 18 from various European Union countries — attended lectures, had Skype conversations with researchers in different countries, worked on a computational project with data from some of the world’s best telescopes, and took part in night-time astronomical observation sessions. Social activities such as hiking, sports, community service activities and film and documentary sessions also contributed to making the camp a fun and enriching experience. While this camp has been running since 2012, it was only opened up ...

3 September 2018: ESO’s La Silla Observatory, situated in northern Chile, offers the resident telescopes unrivalled views of both the cosmos and the region’s barren, but beautiful landscape. Photographed by Alberto Ghizzi Panizza from the ramp leading to ESO’s New Technology Telescope (NTT), this view captures La Silla under the magnificence of the Milky Way, which unmistakably carves its way across the night sky overhead. Sitting proudly at the centre of the frame is the ESO 3.6-metre telescope, host of the planet-hunting HARPS instrument. Below sits the small grey and white enclosure (nicknamed the sarcofago, or sarcophagus) of the Télescope à Action Rapide pour les Objets Transitoires (TAROT). To the far right, the silver-sheened back of the decommissioned 15-metre Swedish-ESO Submillimetre Telescope (SEST) can be seen atop an isolated peak, and, finally, to the left of the road in the foreground sits the corrugated paneling and white dome of the Swiss 1.2-metre Leonhard ...

27 August 2018: This Picture of the Week shows a huge celestial “V” emblazoned across the night sky over ESO’s Paranal Observatory, which is situated atop Cerro Paranal in Chile. One arm of the “V” is noticeably clearer than the other; the right arm, pointing towards the top right corner of the frame, is traced out by the beautiful star-studded centre of the Milky Way. The fainter arm, leaning leftwards, is formed of glowing columns of diffuse zodiacal light, a phenomenon caused by incoming sunlight that is scattered by small particles of cosmic dust. While we often see both the Milky Way and zodiacal light at Paranal thanks to the site’s famously clear skies, the “V” alignment shown here is unusual. Zodiacal light is related to the Earth’s path through space, as the dust particles responsible for scattering the sunlight are all within a cloud that lies on the ecliptic plane (dubbed the ...

20 August 2018: In this spectacular image, taken by ESO Photo Ambassador Petr Horálek, we see the bright arc of the Milky Way stretching across the sky above ESO’s La Silla Observatory in Chile. On the ground are the dome of ESO’s 3.6-metre optical telescope (on the right) and the silvery dish of the Swedish-ESO submillimetre telescope (on the left). Even though it was decommissioned in 2003 to make way for the more advanced APEX and ALMA instruments, the Swedish-ESO dish still seems to be gazing longingly at the sky, perhaps hoping for another chance to explore the mysteries of the heavens. The Milky Way dominates this image, showing clearly why La Silla is one of the best astronomical sites in the world, famed for its dark skies and clear air. From the peak of the bright arc hangs a striking red feature known as Gum Nebula. This, like similar regions along the ...

13 August 2018: This fulldome view of the Very Large Telescope (VLT), at ESO’s Paranal Observatory, shows almost all of the telescope’s constituent units in one family photograph! ESO's VLT comprises four large 8.2-metre Unit Telescopes (UTs), all of which can be seen here and are recognised by their boxy appearance, and four 1.8-metre Auxiliary Telescopes (ATs), two of which are seen here flanking their bigger relatives (both with their rounded domes open). Alongside their standard designations — UT1, UT2, and so on — each of the four giant UTs has its own name in the local Chilean Mapuche language: Antu (The Sun), Kueyen (The Moon), Melipal (The Southern Cross), and Yepun (Venus). The yellow laser streaking up into the night sky, launched by one of the UTs, creates an artificial star high in the atmosphere, fittingly known as a Laser Guide Star (LGS). This ‘star’ is part of the telescope’s adaptive optics ...

6 August 2018: This photo from the Ultra High Definition Expedition to ESO’s La Silla Observatory in Chile shows the Danish 1.54-metre telescope admiring the starry southern skies. The Southern Cross — one of the most distinctive asterisms — can be seen to the left of the telescope’s open dome, nestled in the plane of the Milky Way. The constellation of Crux (The Cross) is best known for this cross-shaped asterism, which comprises four stars — Alpha, Beta, Gamma and Delta Crucis. The closest of these stars, Gamma,Crucis, sits just 88 light-years from Earth, while the furthest is 364 light-years away. The blue–white star Alpha Crucis, the bottom point of the Cross, is the 13th brightest star in the entire night sky. The dark, inky smudge just above the Southern Cross is the Coalsack Nebula, one of the most prominent dark nebulae visible to the naked eye. This opaque cloud of interstellar dust ...

30 July 2018: This ESO Picture of the Week shows a crescent-shaped cocoon of gas and dust — a nebula known as NGC 3199, which lies 12 000 light-years away from Earth. It appears to plough through the star-studded sky like a ship through stormy seas. This imagery is very appropriate due to NGC 3199’s location in Carina — a southern constellation which is named after the keel of a ship! NGC 3199 was discovered by British astronomer John Herschel in 1834 as he compiled his famous catalogue of interesting night sky objects. The nebula has been the subject of numerous observations since, including those by ESO’s 8.2-metre Very Large Telescope (eso0310, eso1117), and 2.6-metre VLT Survey Telescope (VST). The latter made the observations that comprise this image. The nebula’s bright crescent feature is now known to be part of a much larger but fainter bubble of gas and dust. The nebula contains ...

23 July 2018: This image shows a number of antennas from the Atacama Large Millimeter/submillimeter Array (ALMA), a state-of-the-art telescope array positioned high in the Chilean Andes. A full Moon can be seen above the red-tinted horizon, glowing brightly above the observatory. ALMA sits on the Chajnantor Plateau, some 5000 metres above sea level. At this altitude, crystal-clear views of the cosmos can be seen on an almost nightly basis, as shown by the striking cosmic caterpillar gliding over the top of the ALMA antennas in this image. This bright streak is the Milky Way; the galaxy’s bulge of gas and intricate dust lanes is clearly illuminated against the star-studded night sky, with pink-hued patches marking areas of hot, ionised gas produced by newly formed stars. The brightest part of the Milky Way — the very heart of our galaxy — is situated approximately 25 000 light-years away from Earth.

16 July 2018: This photograph, taken by Vincenzo Forchi, provides a unique insight into one of ESO’s most famous — and hard-working — residents. This cacophony of colour, structure and machinery is the interior of the 8.2-metre Unit Telescope 1 (UT1) of ESO’s Very Large Telescope (VLT), at Paranal Observatory in northern Chile. UT1 is more charmingly named Antu, which means The Sun in the region’s indigenous Mapuche language. The other UTs are named after the Moon, the Southern Cross, and Venus — Kueyen, Melipal, and Yepun respectively. Forchi’s image shows Antu as it blinks open its high-tech eye and prepares for a long night observing the cosmos. At the base of the building, artificial lights bathe the area with an incandescent yellow glow. Above, the blue and silver hues of the telescope’s metalwork are complemented by the warm orange embrace of the Sun’s final rays, which scatter off the numerous flaps, or ...

9 July 2018: This photo montage shows a familiar cosmic object — the Moon — in a very unfamiliar way. ESO Photo Ambassador Petr Horálek captured this photoset while visiting ESO’s high-altitude Paranal Observatory in Chile, where skies are remarkably clear. He snapped photographs of this striking blood-red moonset at five-second intervals, watching as the Moon sank through the dark sky before finally dipping below the horizon (the frames are ordered chronologically from left to right, and top to bottom). The prominent red colour of these images is due to the phenomenon of atmospheric refraction. As the Moon approaches the horizon, its reflected light must traverse more and more of the atmosphere before reaching our eyes, meaning that scattering becomes more prominent — in other words, there is more air for the light to push through, and more light is scattered. Of all the colours of visible light, the Earth’s atmosphere scatters and ...

2 July 2018: This image from the Atacama Large Millimeter/submillimeter Array (ALMA) shows MWC 758, a young star that is approaching adulthood and surrounded by knotty, irregular rings of cosmic dust, three of which can be seen here. Unusually, these rings are elliptical in shape rather than being perfectly circular — making this the first discovery of an intrinsically elliptical protoplanetary disc with ALMA! The outer and inner rings each contain one particularly bright clump, visible as arcs of yellow. Additionally there appear to be spiral arms traced out within the dust, as well as a core dust-free cavity that is slightly off-centre. These are all features that hint at the presence of unseen planets. As planets form, they gravitationally interact with the disc and create various telltale features and structures. Astronomers can thus observe a system like MWC 758 and not only infer the existence of potential hidden planets, but also estimate ...

25 June 2018: Sitting between Mars and Jupiter, the doughnut-shaped asteroid belt is packed full of rocky bodies and debris. Despite its fragmented, rubbly nature, the total mass contained within the belt is considerable — roughly four per cent of that of the Moon! The majority of this mass is contained within two distinctive bodies: Ceres, a dwarf planet estimated to make up a third of the mass of the belt, and the asteroid Vesta, which holds around nine per cent of it. Vesta is pictured here. Vesta was recently observed by the SPHERE/ZIMPOL instrument on ESO’s Very Large Telescope (VLT) — the SPHERE image is shown on the left (see the single image here), produced using the MISTRAL algorithm, with a synthetic view derived from space-based data shown on the right for comparison. SPHERE, the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument, is a powerful planet-finding and direct imaging instrument. ZIMPOL is one of ...

18 June 2018: In this spectacular shot from northern Chile, the immediately recognisable and magnificent constellation of Orion (The Hunter) peers down on the small walkway connecting ESO’s 3.6-metre telescope to the now-decommissioned Coudé Auxiliary Telescope, both located at ESO’s La Silla Observatory. A closer look at this long exposure, captured by ESO Photo Ambassador Yuri Beletsky, reveals many interesting features — including a streak of light as an artificial satellite passes behind the telescope’s dome (to the right of the frame). Barnard’s Loop, a faint emission nebula thought to be the remnant of a supernova, appears as a faint reddish arc encircling the bright Orion Nebula. Just below and parallel to the walkway, the dark dust lanes of the Milky Way can be seen rippling across the starry sky. ESO’s 3.6-metre telescope is equipped with the High Accuracy Radial velocity Planet Searcher (HARPS) instrument, one of the most accurate and productive planet ...

11 June 2018: Many telescopes are formed of multiple mirrors or antennas, not just one. ESO’s Very Large Telescope (VLT), located at ESO’s Paranal Observatory in Chile, is a prime example. The VLT comprises four main telescopes, and four smaller, movable auxiliary telescopes — eight individual structures in total. However, even this is dwarfed by the Atacama Large Millimeter/submillimeter Array (ALMA), which sits atop the Chajnantor plateau in the Chilean Andes — and comprises a whopping 66 antennas! Even individually, the ALMA antennas are impressive in size. The Chajnantor plateau itself is also located at an altitude of 5000 metres, with its Operations Support Facility (OSF) at a (still considerable) altitude of 2900 metres. As the antennas are not built up on the plateau, this required an entirely new approach to transporting each of the constituent antennas from the OSF up to Chajnantor. Enter Otto and Lore! Designed and built especially for the ...

4 June 2018: ESO’s La Silla observatory in Chile is unavoidably photogenic from every angle — including unusual and creative perspectives such as this one! This unique panoramic view was captured by ESO Photo Ambassador Petr Horálek. “I was wondering if it was possible to capture the mystical colours of the Universe without complicated equipment,” he explained, adding that he was initially inspired by one of the posters released to accompany Christopher Nolan’s film Interstellar. “At La Silla, you can really feel — and capture — interstellar moments!” Petr evidently succeeded in imaging the Universe in all its beauty. The majestic band of the Milky Way galaxy blazes across the sky, creating a cosmic bridge between two of La Silla’s resident telescopes: the ESO 3.6-metre telescope (left) and the Swedish-ESO Submillimetre Telescope (right). The Large and Small Magellanic Clouds — a duo of nearby galaxies — are captured together sitting “above” the galactic ...

28 May 2018: This ESO Picture of the Week shows the centre of a galaxy named NGC 5643. This galaxy is located 55 million light-years from Earth in the constellation of Lupus (The Wolf), and is known as a Seyfert galaxy. Seyfert galaxies have very luminous centres — thought to be powered by material being accreted onto a supermassive black hole lurking within — that can also be shrouded and obscured by clouds of dust and intergalactic material. As a result, it can be difficult to observe the active centre of a Seyfert galaxy. NGC 5643 poses a further challenge; it is viewed at a high inclination, making it even trickier to view its inner workings. However, scientists have used the Atacama Large Millimeter/submillimeter Array (ALMA) together with archival data from the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s Very Large Telescope to reveal this view of NGC 5643 — complete with ...

21 May 2018: Two spiral galaxies are locked in a spellbinding, swirling dance in this image from the VIMOS instrument on ESO’s Very Large Telescope (VLT). The two interacting galaxies — NGC 5426 and NGC 5427 — together form an intriguing astronomical object named Arp 271, the subject of this, the final image captured by VIMOS before it was decommissioned on 24 March 2018. VIMOS — or, in full, the VIsible Multi-Object Spectrograph — was active on the VLT for an impressive 16 years. During that time it helped scientists to uncover the wild early lives of massive galaxies, observe awe-inspiring triple-galaxy interactions, and explore deep cosmic questions such as how the Universe’s most massive galaxies grew so large. Instead of focusing on single objects, VIMOS was able to capture detailed information about hundreds of galaxies at once. This sensitive instrument collected the spectra of tens of thousands of galaxies throughout the Universe, ...

14 May 2018: Twinkling stars are far more desirable to poets and romantics than to astronomers. Even in the near-pristine seeing conditions over Chile, home to ESO’s fleet of world-class telescopes, turbulence in Earth’s atmosphere causes stars to twinkle, blurring our view of the night sky. These four laser beams are specially designed to combat this turbulence. The intense orange beams dominating this image originate from the 4 Laser Guide Star Facility, a state-of-the-art component of the Adaptive Optics Facility of ESO’s Very Large Telescope (VLT). Each beam is some 4000 times more powerful than a standard laser pointer! Each creates an artificial guide star by exciting sodium atoms high in the Earth’s upper atmosphere and causing them to glow. Creating artificial guide stars allows astronomers to measure and correct for atmospheric distortion, by adjusting and calibrating the settings of their observing equipment to be as accurate as possible for that particular area ...

7 May 2018: In an astronomically unlikely coincidence, a star exploded as a nova in the sky over the Supernova Planetarium & Visitor centre less than a week after its inauguration. An image of the dwarf nova V392 Persei was captured by ESO photo ambassador Petr Horálek on 2 May 2018. It shows a wide angle view of the evening sky over the ESO Supernova, looking west-northwest. The position of the nova over the ESO Supernova is marked on the wide view with an insert showing a zoomed view of the area taken with same camera but using a different lens. In this image the nova is easily identifiable due to its typical orange colour. Dwarf novae occur as a result of a white dwarf star accreting material from its lower mass, binary companion. The material from the disc is compressed as it is transferred to the surface of the white dwarf where ...