Picture of the Week 2024

5 February 2024: Why use just one telescope to observe the sky? The plateau of Cerro Paranal, seen under the moonlight in this Picture of the Week, hosts ESO’s Very Large Telescope Interferometer (VLTI), an indomitable team of four 8.2-metre Unit Telescopes (UTs) and four additional 1.8-metre Auxiliary Telescopes (ATs). An interferometer precisely combines light from separate telescopes observing the same object in the sky, allowing astronomers to see the cosmos in incredible detail. The VLTI uses either a combination of the ATs or the UTs. The ATs, one of which is seen front and centre, are set on tracks so they can be moved to 30 predefined positions on the platform, in different configurations; each arrangement allows astronomers to observe different levels of detail. While the ATs are specifically designed for the VLTI, each UT can be also used as an independent telescope. One of the UTs is equipped with lasers that ...

29 January 2024: Like a flower following the Sun, the dome of ESO’s Extremely Large Telescope (ELT) will be able to rotate to allow the telescope to track objects in the sky. Seen under the bright blue skies of Cerro Armazones in the Chilean Atacama Desert, this video shows a test of the dome rotating for the first time. The test moved the dome 10 m in either direction at 1 cm/s, but the final operating speed will be a walking pace of 5 km/h. The test was performed by engineers of Cimolai, the company contracted by ESO to design and build the ELT dome and telescope structure. The humans hard at work in this sped-up video show, for scale, the sheer size of the telescope dome. Rotating the dome is no small feat, as its skeleton currently weighs about 2500 tons, and will eventually weigh around 6100 tons when finished. This first ...

22 January 2024: In December 2023, the first 18 segments of ESO’s Extremely Large Telescope (ELT) main mirror embarked on a whirlwind 10 000 km journey from Europe to the Chilean Atacama Desert. This Picture of the Week captures the moment of truth when ESO engineers at the ELT Technical Facility unveiled one of the segments to ensure it had arrived safely at ESO’s Paranal Observatory. Due to the sheer size and fragility of the mirror segments —each mirror is five centimetres thick, 1.5 metres wide and shaped to nanometre accuracy— they were each shipped in a private, protective cocoon. Each box was equipped with humidity, temperature and shock sensors to track the internal conditions during the long journey. When loaded into the transport vehicles, the boxes were cushioned by air bags. Upon arrival at the technical facility, the segments were carefully inspected to ensure they hadn’t been damaged during delivery. With the ...

15 January 2024: The Vela constellation is visible with the naked eye in the southern sky, but you might miss a lot of details hidden there, like those shown in this Picture of the Week. This is a small patch of the Vela supernova remnant, the intricate leftovers of the explosion of a massive star 11 000 years ago. This image is part of a huge and detailed mosaic captured with the VLT Survey Telescope (VST), hosted at ESO’s Paranal Observatory in the Chilean desert. Pink and orange filamentary clouds swarm around in this picture, resembling the ghostly shadow of a cosmic bird with wide orange wings, a long pink body, and a bright pinkish star as an eye. A myriad of stars are sprinkled all over the image. When massive stars reach the end of their life they explode as supernovae, expelling their outer layers. These explosions send out shock waves that ...

8 January 2024: The high altitude and dry air of the Chajnantor plateau give the Atacama Large Millimeter/submillimeter Array (ALMA), operated by ESO and its international partners, an optimal window to study the cold dark universe. In this striking Picture of the Week, the rolling, rusty and barren landscape of the plateau feels more like an alien world, rather than our own planet. Thankfully, a familiar friend brings us back to Earth — the full Moon rising at sunset. Over the different lunar phases, the moon rises and sets at different times, while over the course of the year, it rises and sets in different locations on the horizon. Set against the horizon during its rise, the moon often seems to loom larger than usual. But this is only a trick on your eyes due to a famed optical illusion. Our Moon is a unique body within the solar system; it’s Earth’s only ...

1 January 2024: Firework displays are used to mark the beginning of the New Year all over the world, so we thought we’d bring you our own, space-themed display to kick things off in 2024. This Picture of the Week is a time-lapse video of the night sky above ESO’s Very Large Telescope (VLT) on Cerro Paranal, Chile. Look closely, and you’ll catch a glimpse of an extraterrestrial firework, otherwise known as a meteor. Meteors are objects from outer space that burn up as they enter Earth's atmosphere at high speeds. Often called “shooting stars” or “fireballs”, they create dazzling displays as they crash through our gaseous atmosphere, heating up as a result of friction with the air. In this sped-up time-lapse, captured in June last year, the meteor left behind a trail of smoke that slowly dispersed in the atmosphere. By some estimates, 44 tonnes of meteoric material fall into Earth’s atmosphere ...