Picture of the Week

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potw1322 — Picture of the Week
Three Planets Dance Over La Silla
3 June 2013: It’s a real treat for photographers and astronomers alike: our skies are currently witnessing a phenomenon known as a syzygy — when three celestial bodies (or more) nearly align themselves in the sky. When celestial bodies have similar ecliptic longitude, this event is also known as a triple near-conjunction. Of course, this is just a trick of perspective, but this doesn't make it any less spectacular. In this case, these bodies are three planets, and the only thing needed to enjoy the show is a clear view of the sky at sunset. Luckily, this is what happened for ESO photo ambassador Yuri Beletsky, who had the chance to spot this spectacular view from ESO's La Silla Observatory in northern Chile on Sunday 26 May. Above the round domes of the telescopes, three of the planets in our Solar System — Jupiter (top), Venus (lower left), and Mercury (lower right) — ...
potw1321 — Picture of the Week
Ripples Across the Chilean Sky
27 May 2013: At first sight, this mesmerising image might look like the waves caused by a stone thrown into a lake. And yet, this is the result of the apparent motion of the stars through the southern sky and some magic performed by the photographer. The image was taken at Cerro Armazones, a mountain peak 3060 metres above sea level, which lies in the central part of the Atacama Desert, in the Chilean Andes. The long bright stripes are star trails and each one marks the path of a single star across the dark night sky. By leaving the camera’s shutter open for a long period of time, the movement of the stars, imperceptible to the naked eye, is revealed. Exposure times of as little as 15 minutes are long enough to do the trick. In this case, the photographer combined many shorter exposures to form the final image. The very wide-angle ...
potw1320 — Picture of the Week
Admiring the Galaxy
20 May 2013: It is difficult for even the most seasoned astronomer to resist taking time out of a busy observing schedule to stop and stare up at the gloriously rich southern sky. This image is a self portrait taken by astronomer Alan Fitzsimmons, who took this photo between observing sessions at ESO’s La Silla Observatory. This bold photo shows the contrast between a simple, still and dark figure on Earth and the brilliant and bright starry night sky. In this picture, the sky is dominated by the enormous splash of stars and dust which make up the centre of the Milky Way, our home galaxy. ESO’s observatories are located in the Atacama Desert in northern Chile, a region with very few inhabitants, which combines very dark nights with extremely clear atmospheric conditions, both factors conducive to making high quality observations. La Silla is ESO’s first observatory. Inaugurated in 1969, it is home ...
potw1319 — Picture of the Week
Milky Way Shines over Snowy La Silla
13 May 2013: In the outskirts of the Atacama Desert, far from the light-polluted cities of northern Chile, the skies are pitch-black after sunset. Such dark skies allow some of the best astronomical observing to take place — and at an altitude of 2400 metres, ESO’s La Silla Observatory has an incredibly clear view of the night sky. However, even such a remote, high, and dry location cannot always escape the weather that sometimes comes with the winter months, when blankets of snow can cover the mountain peak and its telescope domes. This image shows a wintry La Silla sitting beneath a spray of stars from our Milky Way, the plane of which slants across the frame. Visible (from right to left) are the ESO 3.6-metre telescope, the 3.58-metre New Technology Telescope (NTT), the ESO 1-metre Schmidt telescope, and the MPG/ESO 2.2-metre telescope, which has snow on its dome. The small dome of ...
potw1318 — Picture of the Week
Lore on the Move
6 May 2013: In this photograph one of the two ALMA transporters, Lore, is carrying one of the 7-metre-diameter antennas of ALMA, the Atacama Large Millimeter/submillimeter Array. Lore and her twin, Otto, are two bright yellow 28-wheeled vehicles, custom-built to move ALMA’s antennas around on the Chajnantor Plateau at an elevation of 5000 metres. By doing this, they can reconfigure the telescope array to make the most useful observations of a given target. They also move antennas between Chajnantor and the lower altitude Operations Support Facility for maintenance.ALMA has a main array of fifty 12-metre-diameter antennas, and an additional array of twelve 7-metre antennas and four 12-metre antennas, known as the Atacama Compact Array (ACA). Lore is carrying one of the smaller, 7-metre antennas of the ACA. The 12-metre antennas of the main array cannot be placed closer than 15 metres apart as they would otherwise bump into each other. This minimum separation ...
potw1317 — Picture of the Week
Wings for Science Fly Over ALMA
29 April 2013: This beautiful image, taken in December 2012, shows the array of antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) [1], the largest astronomy project in existence, located at the Chajnantor Plateau in the Chilean Andes. The large antennas are 12 metres in diameter, and the smaller ones, gathered together in the middle of the image, form the ALMA Compact Array (ACA), which is made up of 12 antennas with a diameter of 7 metres. When the array is completed, there will be a total of 66 antennas. ESO has initiated an outreach partnership with the ORA Wings for Science project, a non-profit organisation which offers aerial support to public research while on a year-long journey around the world. The two crew members of the Wings for Science Project, Clémentine Bacri and Adrien Normier, fly a special environmentally friendly ultralight [2] to help out scientists by providing aerial capabilities ranging from ...
potw1316 — Picture of the Week
Silver and Blue at Paranal
22 April 2013: What might count as a beautifully clear day anywhere else in the world is actually an unusually cloudy day at ESO’s Paranal Observatory in the Atacama Desert. As this is one of the driest places on the planet, it is very uncommon to see clouds in the sky. Many astronomers and engineers who spend time at the site find the cloudless sky one of the most striking things about working in the Atacama Desert. This gorgeous 360-degree panorama photo, taken by ESO contractor Dirk Essl in 15 separate exposures, has captured one of the rare days with clouds at Paranal. A few thin, wispy cirrus clouds can be seen above the enclosures of the Very Large Telescope. These clouds form at high altitudes and are made up of tiny ice crystals.Paranal Observatory receives less than 10 millimetres of rainfall per year, which is just one of the reasons why this ...
potw1315 — Picture of the Week
Under the Spell of the Magellanic Clouds
15 April 2013: This beautiful image of the Atacama Large Millimeter/submillimeter Array (ALMA), showing the telescope’s antennas under a breathtaking starry night sky, comes from Christoph Malin, an ESO Photo Ambassador. This is a still frame taken from one of his painstakingly created time-lapse videos of ALMA, which are also available (see ann12099).Located on the Chajnantor Plateau at an elevation of 5000 metres, ALMA is the world’s most powerful telescope for studying the Universe at submillimetre and millimetre wavelengths. Construction work for ALMA will be completed in 2013, and a total of 66 of these high-precision antennas will be operating on the site. Glowing brightly in the sky, the Large and Small Magellanic Clouds stand out above the antennas. These nearby irregular dwarf galaxies are conspicuous objects in the southern hemisphere, even with the naked eye. These galaxies are both orbiting the Milky Way — our galaxy — and there is evidence that ...
potw1314 — Picture of the Week
A Sparkling Ribbon of Stars — The Southern Milky Way over La Silla
8 April 2013: This panoramic photograph, taken by Alexandre Santerne, shows an insider’s view of the disc of the Milky Way, our home galaxy, as well as a cold winter’s night, with a sprinkling of snow at ESO’s La Silla Observatory in Chile. From our vantage point within it, the disc of the Milky Way appears as a sparkling ribbon of stars stretching across the sky. In this panorama, the Milky Way is distorted into an arc by the wide-angle projection. Peeking over the hill on the left of this photo is the ESO 3.6-metre telescope, home to the world's foremost exoplanet hunter, HARPS (the High Accuracy Radial velocity Planet Searcher). On the far right is the Swiss 1.2-metre Leonhard Euler Telescope, built and operated by the Geneva Observatory. There are a number of reasons why La Silla is such an ideal location for observing the night sky in general, and the Milky ...
potw1313 — Picture of the Week
Stars Circle over the Residencia at Cerro Paranal
1 April 2013: This image from ESO Photo Ambassador Farid Char, of the southern night sky over the Residencia “hotel” at ESO’s Paranal Observatory in Chile, presents a beautifully star-filled and dynamic view of the heavens. To make the swirling star trails on this image, Farid used a 30-minute exposure to reveal the observed movement of the stars due to the rotation of the Earth. In the centre is the apparently still point of the south celestial pole. On the left, and at the top of the image, are the extended blurs of the Large and Small Magellanic Clouds, neighbouring galaxies of the Milky Way. The dark glass dome below the circling stars is part of the roof of the Residencia building. This unique partially subterranean construction has been in use since 2002 by scientists and engineers working at the observatory. During the day, the 35-metre-wide dome allows natural daylight into the building. ...
potw1312a — Picture of the Week
The Lost Galaxy
25 March 2013: This image depicts the galaxy NGC 4535, in the constellation of Virgo (The Maiden), on a beautiful background full of many distant faint galaxies. Its almost circular appearance shows that we observe it nearly face-on. In the centre of the galaxy, there is a well-defined bar structure, with dust lanes that curve sharply before the spiral arms break from the ends of the bar. The bluish colour of the spiral arms points to the presence of a large number of hot young stars. In the centre, however, older and cooler stars give the bulge of the galaxy a yellower appearance. This visible image was made with the FORS1 instrument on ESO’s 8.2-metre Very Large Telescope. The galaxy can also be seen through smaller amateur telescopes, and was first observed by William Herschel in 1785. When seen through a smaller telescope, NGC 4535 has a hazy, ghostly appearance, which inspired the ...
potw1311 — Picture of the Week
Catching Light
18 March 2013: Research telescopes sport state-of-the-art cameras which, together with the big mirrors needed for a large collecting area, allow astronomers to catch the faint light of deep sky objects. But you can also produce beautiful images without big telescopes and using more modest cameras. Astrophotographers use more conventional cameras to capture images of astronomical objects, often on a larger scale than the observations made with big telescopes. Sometimes, they include the landscape in their composition, producing beautiful postcards of the Universe as seen from Earth. For example, this Picture of the Week shows the 3.58-metre New Technology Telescope (NTT), located at ESO’s La Silla Observatory, and set against the starry background of the southern sky. Standing out in the image, the Milky Way — our home galaxy — can be seen as a hazy stripe across the sky. Dark regions within the Milky Way are areas where the light from background ...
potw1310 — Picture of the Week
Comets and Shooting Stars Dance Over Paranal
11 March 2013: This impressive picture was taken on 5 March 2013 by Gabriel Brammer, one of the ESO Photo Ambassadors, and shows a sunset view of the Paranal Observatory, featuring two comets that are currently moving across the southern skies. Close to the horizon, on the right-hand side of the image, Comet C/2011 L4 (Pan-STARRS), the brightest of the two, shows a bright tail that is caused mainly by dust reflecting the sunlight. In the centre of the image, just above the right-hand slopes of Cerro Paranal, the greenish coma — a nebulous envelope around the nucleus — of Comet C/2012 F6 (Lemmon) can be distinguished, followed by a fainter tail. The green colour is a result of the ionisation of gases in the coma by sunlight. You might even be tricked into thinking that there is a third comet visible in this photo, but the bright object whizzing between comets Lemmon and ...
potw1309 — Picture of the Week
Snow Comes to the Atacama Desert
4 March 2013: The Atacama Desert is one of the driest places in the world. Several factors contribute to its arid conditions. The magnificent Andes mountain range and the Chilean Coast Range block the clouds from the east and west, respectively. In addition, the cold offshore Humboldt Current in the Pacific Ocean, which creates a coastal inversion layer of cool air, hinders the formation of rain clouds. Moreover, a region of high pressure in the south-eastern Pacific Ocean creates circulating winds, forming an anticyclone, which also helps to keep the climate of the Atacama Desert dry. These arid conditions were a major factor for ESO in placing the Very Large Telescope (VLT) at Paranal, in the Atacama Desert. At the Paranal Observatory, located on the summit of Cerro Paranal, the precipitation levels are usually below ten millimetres per year, with the humidity often dropping below 10%. The observational conditions are excellent, with over ...
potw1308 — Picture of the Week
The Comet and the Laser
25 February 2013: Gerhard Hüdepohl, one of the ESO Photo Ambassadors, captured this spectacular image of ESO’s Very Large Telescope (VLT) during the testing of a new laser for the VLT 14 February 2013. It will be used as a vital part of the Laser Guide Star Facility (LGSF), which allows astronomers to correct for most of the disturbances caused by the constant movement of the atmosphere in order to create much sharper images. Nevertheless, is hard not to think of it as a futuristic laser cannon being pointed towards some kind of distant space invader. As well as the amazing view of the Milky Way seen over the telescope, there is another feature making this picture even more special. To the right of the centre of the image, just below the Small Magellanic Cloud and almost hidden among the myriad stars seen in the dark Chilean sky, there is a green dot with a faint tail ...
potw1307 — Picture of the Week
Super-thin Mirror Under Test at ESO
18 February 2013: This remarkable deformable thin-shell mirror has been delivered to ESO at Garching, Germany and is shown undergoing tests. It is 1120 millimetres across but just 2 millimetres thick, making it much thinner than most glass windows. The mirror is very thin so that it is flexible enough for magnetic forces applied to it to alter the shape of its reflective surface. When in use, the mirror's surface will be constantly changed by tiny amounts to correct for the blurring effects of the Earth’s atmosphere and so create much sharper images. The new deformable secondary mirror (DSM) will replace the current secondary in one of the VLT’s four Unit Telescopes. The entire secondary structure includes a set of 1170 actuators that apply a force on 1170 magnets glued to the back face of the thin shell. Sophisticated special-purpose electronics control the behaviour of the thin shell mirror. The reflecting surface can ...
potw1306 — Picture of the Week
Laser and Light Painting
11 February 2013: On a clear night in Bavaria, ESO staff attended the filming of an ESOcast episode focusing on ESO’s new compact laser guide star unit, seen here in action at the Allgäu Public Observatory in Ottobeuren, Germany. Using the glow from their mobile phones, staff took advantage of the long-exposure photograph to draw the letters “ESO” in light, while standing in front of the observatory. Just left of the vertical laser beam, the Milky Way can be seen. Just above the horizon over the observatory, the dotted tracks of aircraft can be seen in the distance. The laser has a powerful beam of 20 watts, and to protect pilots and passengers a no-fly zone around the observatory was created by the Deutsche Flugsicherung (responsible for air traffic control in Germany) during the nighttime observing hours. Laser guide stars are artificial stars created in the Earth’s atmosphere using a laser beam. The ...
potw1305 — Picture of the Week
Sunset at Paranal Observatory
4 February 2013: Babak Tafreshi, an ESO Photo Ambassador, has captured a beautiful image of ESO’s Paranal Observatory illuminated by the sunset. The beautifully clear sky hints at the exceptional atmospheric conditions here; one major reason why ESO chose Paranal as the site of the Very Large Telescope (VLT), its flagship facility.The VLT — which can be seen on Cerro Paranal, the highest peak in the image, with an altitude of 2600 metres —  is the world’s most advanced visible-light astronomical observatory. It consists of four Unit Telescopes, each with a primary mirror 8.2 metres across, and four 1.8-metre Auxiliary Telescope. The VLT operates at visible and infrared wavelengths and among the pioneering observations carried out using the VLT have been the first direct image of an exoplanet (see eso0515) and the tracking of stars orbiting the Milky Way’s central black hole (see eso0846 and eso1151). Also on Cerro Paranal is the VLT ...
potw1304 — Picture of the Week
An Intergalactic Heavyweight
28 January 2013: This deep-field image shows what is known as a supercluster of galaxies — a giant group of galaxy clusters which are themselves clustered together. This one, known as Abell 901/902, comprises three separate main clusters and a number of filaments of galaxies, typical of such super-structures. One cluster, Abell 901a, can be seen above and just to the right of the prominent red foreground star near the middle of the image. Another, Abell 901b, is further to the right of Abell 901a, and slightly lower. Finally, the cluster Abell 902 is directly below the red star, towards the bottom of the image. The Abell 901/902 supercluster is located a little over two billion light-years from Earth, and contains hundreds of galaxies in a region about 16 million light-years across. For comparison, the Local Group of galaxies — which contains our Milky Way among more than 50 others — measures roughly ...
potw1303 — Picture of the Week
APEX Under the Moon
21 January 2013: Another starry night on the Chajnantor Plateau in the Chilean Andes. The first quarter Moon glows brightly in this exposure, outshining the surrounding celestial objects. However, for radio telescopes such as APEX (the Atacama Pathfinder Experiment), seen here, the brightness of the Moon is not a problem for observations. In fact, since the Sun itself is not too bright at radio wavelengths, and these wavelengths do not brighten the sky in the same way, this telescope can even be used during the daytime, as long as it is not pointed towards the Sun. APEX is a 12-metre-diameter telescope that observes light at millimetre and submillimetre wavelengths. Astronomers observing with APEX can see phenomena which would be invisible at the shorter wavelengths of infrared or visible light. For instance, APEX can peer through dense interstellar clouds of gas and cosmic dust, revealing hidden regions of ongoing star formation which glow brightly ...
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