Picture of the Week

21 September 2009: Cerro Paranal, in the Chilean Atacama Desert, is considered one of the best astronomical observing sites in the world. It is home to ESO’s Very Large Telescope (VLT), the flagship facility for European ground-based astronomy. The humidity at Paranal is generally below five percent and the overall precipitation is only 4 mm per year — a rather dry place indeed. It does, on very rare occasions, snow on this 2600-metre-high peak as illustrated by this beautiful image taken in 2002. The snow-covered terrain gleams under a bright blue sky as the snow storm passes.

14 September 2009: In this image, two spiral galaxies, similar in looks to the Milky Way, are participating in a cosmic ballet, which, in a few billion years, will end up in a complete galactic merger — the two galaxies will become a single, bigger one. Located about 150 million light-years away in the constellation of Canis Major (the Great Dog), NGC 2207 — the larger of the two — and its companion, IC 2163, form a magnificent pair. English astronomer John Herschel discovered them in 1835. The fatal gravitational attraction of NGC 2207 is already wreaking havoc throughout its smaller partner, distorting IC 2163’s shape and flinging out stars and gas into long streamers that extend over 100,000 light-years. The space between the individual stars in a galaxy is so vast, however, that when these galaxies collide, virtually none of the stars in them will actually physically smash into each other. This ...

7 September 2009: In this photograph taken on 18 August 2009, a European ALMA antenna takes shape at the observatory's Operations Support Facility (OSF). ALMA, the Atacama Large Millimeter/submillimeter Array, is a revolutionary astronomical telescope, comprising an array of 66 giant 12-metre and 7-metre diameter antennas observing at millimetre and submillimetre wavelengths. The telescope is being built on the breathtaking location of the Chajnantor plateau, at 5000 metres altitude in the Chilean Andes. The OSF, at which the antennas are being assembled and tested, is at an altitude of 2900 metres. ESO has contracted with the AEM (Alcatel Alenia Space France, Alcatel Alenia Space Italy, European Industrial Engineering S.r.L., MT Aerospace) Consortium for the supply of 25 of the 12-metre diameter ALMA antennas, with options to increase the number to 32. ALMA is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile.

31 August 2009: Stars such as our Sun do not contain enough mass to finish their lives in the glorious explosions known as supernovae. However, they are still able to salute their imminent demise into dense, Earth-sized embers called white dwarfs by first expelling colourful shells of gas known as planetary nebulae. This misnomer comes from the similarity in appearance of these spherical mass expulsions to giant planets when seen through small telescopes. NGC 6781 is a nice representative of these cosmic bubbles. The planetary nebula lies a few thousand light-years away towards the constellation of Aquila (the Eagle) and is approximately two light-years across. Within NGC 6781, shells of gas blown off from the faint, but very hot, central star’s surface expand out into space. These shells shine under the harsh ultraviolet radiation from the progenitor star in intricate and beautiful patterns. The central star will steadily cool down and darken, eventually ...

24 August 2009: The great hunter Orion hangs above ESO’s Very Large Telescope (VLT), in this stunning, previously unseen, image. As the VLT is in the Southern Hemisphere, Orion is seen here head down, as if plunging towards the Chilean Atacama Desert. At night the four giant 8.2-metre Unit Telescopes of the VLT are all turned skywards to help astronomers in their quest to understand the Universe. The band of the Milky Way, crisscrossed by contrasting dark dust lanes, stretches up over the VLT’s Unit Telescope 3 (Melipal), with the bright star Capella glinting just above the telescope. Up and to the left, Orion’s belt and sword, containing the Orion Nebula, lie between the blue star Rigel and the orange Betelgeuse. The red Rosetta Nebula is seen in the middle part of the Milky Way, while Sirius, the brightest star in the night sky, hangs above the scene. The red patch just above ...

17 August 2009: This image shows the platform on the summit of Cerro Paranal, in Northern Chile that houses the ESO Very Large Telescope (VLT). Three of the enclosures protecting the 8.2-metre diameter VLT Unit Telescopes (UTs) are shown and the photographer was on the top of the fourth one, about 35 metres above the platform. At night the huge doors in the enclosures slide open and the 275-tonne top parts of these buildings rotate so that the telescope can observe any part of the sky. The pick-up truck in front of the first UT helps give the scale of this 10-story high building. On the left of the image the rails on which the 1.8-metre Auxiliary Telescopes (ATs) can be moved to different observing stations are visible. Two of the four ATs are visible in the picture. The low building in the lower left corner houses the VLT Interferometer laboratory, where the ...

10 August 2009: This new image of the galaxy NGC 2280 shows the extent of its massive spiral arms that reach far into the surrounding space. These star-filled tentacles taper off into wispy blue clouds of illuminated and glowing gas well away from the central, bright bulge of the galaxy. Found towards the constellation of Canis Major (the Greater Dog), NGC 2280 is thought to be similar in shape to our own Milky Way galaxy. NGC 2280 whirls in the cosmos about 75 million light-years from us; this snapshot therefore shows the galaxy as it appeared when dinosaurs still roamed the Earth. The very bright stars that sparkle like diamonds in the image, as well as the many other stars of various colours, are all in the foreground of our view, as they lie much closer to us than NGC 2280. The image was captured with the ESO Faint Object Spectrograph and Camera ...

3 August 2009: The Milky Way blazes above the European Southern Observatory (ESO) facilities at Mount Paranal in northern Chile’s Atacama Desert. Paranal hosts the world’s most advanced ground-based astronomical observatory, the Very Large Telescope (VLT), and is home to two new telescopes for large imaging surveys currently under construction, the VLT Survey Telescope (VST) and the Visible and Infrared Survey Telescope for Astronomy (VISTA). Both are expected to “take up duty” in the 2009-2010 timeframe. This photograph shows an edge-on view of the Milky Way’s glowing plane slicing across the night sky, laced by bands of dust and dark gas. Taken with a digital camera using a three-minute exposure, the photograph also reveals a bit of action on the ground. To the left, a vehicle with its parking lights on stops lets out a passenger. Though bathed by the light of the Milky Way, the high-altitude desert remains quite dark. To illuminate ...

27 July 2009: This image shows how ESO’s Very Large Telescope (VLT) facility looks through the eyes of Google Earth. This popular software allows users to see the world from above, ranging from a satellite to a bird’s eye view. Now, Google Earth users can swoop around detailed 3-D models of the massive structures housing the four 8.2-metre Unit Telescopes (UTs) atop Mount Paranal in the Chilean Atacama Desert. Also visible in this sample image are the four 1.8-metre movable Auxiliary Telescopes (ATs), the enclosure of the 2.4-metre VLT Survey Telescope (VST), and technical and support buildings. The models can be downloaded from ESO’s VLT page, and opened using Google Earth.

20 July 2009: This new artist’s impression shows the future Extremely Large Telescope (ELT), which is currently being planned by ESO. This revolutionary new ground-based telescope will be the largest optical/near-infrared telescope ever conceived, and will serve as “the world’s biggest eye on the sky”. The present concept is for a telescope with a mirror 39 metres in diameter, able to capture images of the sky about a tenth the size of the full Moon. The telescope will contain five mirrors, a novel configuration that results in exceptional image quality. The largest (primary) mirror will consist of almost 800 segments, each 1.4 metres wide but only 50 mm thick. The optical system’s design also calls for an immense secondary mirror measuring 4.2 metres in diameter, which is almost as large as the biggest primary mirrors used in today’s telescopes. With the start of operations planned early in the next decade, the ELT will ...

13 July 2009: This photograph from early 2009 shows the VISTA telescope, which is currently completing tests in its dome at Paranal in Chile. VISTA, along with the VST (VLT Survey Telescope) is one of two ESO survey telescopes about to start work surveying the southern skies. VISTA has a main mirror that is 4.1 metres across and is by far the largest telescope in the world dedicated to surveying the sky at near-infrared wavelengths. It was conceived and developed by the United Kingdom and became an in-kind contribution to ESO as part of the UK's accession agreement, with the subscription paid by the UK Science and Technology Facilities Council (STFC). The main mirror is the most highly curved mirror of its size ever made and at the heart of VISTA is a 3-tonne camera containing 16 special detectors sensitive to infrared light with a combined total of 67 megapixels. It will have ...

6 July 2009: Excavation work has just begun for construction of the Santiago Central Office (SCO) building of the Atacama Large Millimeter/submillimeter Array (ALMA) project. The building, in the Vitacura district of the Chilean capital, will be adjacent to the Santiago offices of the European Southern Observatory (ESO), which is the European partner in the global ALMA project, and which is responsible for constructing the ALMA SCO. The SCO building will have a size of almost 7,000 square metres over two storeys, with underground parking for 130 cars, which will allow some of the existing above-ground parking spaces to be moved underground and replaced with green areas. For the construction, eleven old trees were moved to a new location at ESO, in a meticulous operation led by experts. ALMA, the largest astronomical project in existence, is a revolutionary astronomical telescope, comprising an array of 66 giant 12-metre and 7-metre diameter antennas observing at ...

29 June 2009: The Atacama Large Millimeter/submillimeter Array (ALMA) is the largest astronomical project in existence. It is a revolutionary astronomical telescope, comprising an array of 66 giant 12-metre and 7-metre diameter antennas observing at millimetre and submillimetre wavelengths. It is being built on the breathtaking location of the Chajnantor plateau, at 5000 metres altitude in the Chilean Andes, and will start scientific observations in 2011. In this artist’s rendering, the ALMA array is seen on the Chajnantor plateau in an extended configuration. The antennas, which each weigh over 100 tons, can be moved to different positions with custom-built transporter vehicles in order to reconfigure the array. ALMA is the most powerful telescope for observing the cool Universe — molecular gas and dust as well as the relic radiation of the Big Bang. It will study the building blocks of stars, planetary systems, galaxies and life itself. ALMA, an international astronomy facility, is ...

22 June 2009: This Quicktime interactive panorama movie shows the night sky over ESO’s Paranal Observatory in Chile and reveals its incredible richness and beauty. To launch the panorama please click the link on the right under QuickTime VR. To navigate this dual landscape and starscape, left-click on the image and continue pressing the button as you drag the mouse in the direction you would like to see. To zoom in and out, press "shift" or "ctrl". Moving towards the right, the panorama shows the Milky Way band blazing over the horizon. Ascending the mountain that comes into view, one sees ESO’s Very Large Telescope array and the red beam of its Laser Guide Star. Still further right, the VISTA peak rises, with the lingering Gegenschein aglow above it. Other sights in the sky over Paranal include the Andromeda Galaxy, the Pleiades and the Hyades star clusters, the constellation of Orion, and the ...

15 June 2009: NGC 2613 is a rarely imaged spiral galaxy located about 60 million light years away towards the southern constellation of Pyxis (the mariner’s compass). It is thought to resemble our own Milky Way. This image is based on data acquired with the 1.5-metre Danish telescope at ESO’s La Silla Observatory in Chile, through three filters (B, V, R).

8 June 2009: Three of the four Unit Telescopes of ESO’s Very Large Telescope (VLT) are shown here getting ready for another exceptional night of observations on top of Cerro Paranal, in Chile. Prior to every night, the engineers in charge go through a routine of manoeuvres to prepare the flagship facility of European astronomy. The VLT is the world’s most advanced optical instrument, consisting of four Unit Telescopes with main mirrors of 8.2-metre diameter and four movable 1.8-metre diameter Auxiliary Telescopes. One of the Auxiliary Telescopes is shown on the right of the image.

2 June 2009: Centaurus A is our nearest giant galaxy, at a distance of about 13 million light-years in the southern constellation of Centaurus, and as such, it is one of the most extensively studied objects in the southern sky. It is an elliptical galaxy, currently merging with a companion spiral galaxy, resulting in areas of intense star formation and making it one of the most spectacular objects in the sky. Centaurus A hosts a very active and highly luminous central region, caused by the presence of a supermassive black hole with a mass of about 100 million solar masses (see eso0109), and is the source of strong radio and X-ray emission. Thick dust layers almost completely obscure the galaxy's centre. This image is based on data acquired with the 1.5-metre Danish telescope at ESO’s La Silla Observatory in Chile, through three filters (B, V, R).

25 May 2009: The Moon is normally much too large and bright to be a target for the 8.2-metre Unit Telescopes (UTs) that make up ESO’s Very Large Telescope, whose sheer power is best reserved for much fainter and much more distant astronomical objects, such as exoplanets or exploding stars located at the edge of the visible Universe. But back in 2002, one of the UTs was not yet equipped with an instrument at one of its Nasmyth platforms (located on the side of the telescope), and astronomers and engineers could have an unusual view of our natural satellite. In this case, the Moon's image was projected onto a sandblasted glass plate. Since then, the Very Large Telescope has been equipped with no less than 14 instruments, including three for interferometry, making it truly the world’s most advanced observatory.

18 May 2009: Located about 15 million light-years away towards the Hydra (the sea serpent) constellation, Messier 83 is a nearby face-on barred spiral with a classic grand design form. It is the main member of a small galactic group including NGC 5253 and about 9 dwarf galaxies. Messier 83 stretches over 40,000 light-years, making it roughly 2.5 times smaller than our own Milky Way. However, in some respects, Messier 83 is quite similar to our own galaxy. Both the Milky Way and Messier 83 possess a bar across their galactic nucleus, the dense spherical conglomeration of stars seen at the centre of the galaxies. Messier 83 has been a prolific producer of supernovae, with six observed in the past century. This is indicative of an exceptionally high rate of star formation coinciding with its classification as a starburst galaxy. Despite its symmetric appearance, the central 1,000 light-years of the galaxy shows an ...

11 May 2009: View from inside the main building of the 2,900 metre high ALMA Operation Support Facility. Three antennas currently being tested are seen outside. On 30 April, scientists and engineers working on the world’s largest astronomical project, the Atacama Large Millimeter/submillimeter Array (ALMA), have achieved the successful linking of two ALMA astronomical antennas, synchronised with a precision of one millionth of a millionth of a second, to observe the planet Mars. The observations demonstrate ALMA’s full hardware functionality and connectivity. When completed around 2012, ALMA will comprise an array of 66 giant 12-metre and 7-metre diameter antennas observing at millimetre and submillimetre wavelengths.Read more about this milestone in eso0918.