The Extremely Large Telescope’s Dome is on the Move

A webcam image of the construction of the Extremely Large Telescope (ELT) located on Cerro Armazones in the Chilean Atacama Desert, on January 29, 2024. Credit: ESO.

Construction of the Extremely Large Telescope (ELT) reached a milestone, with the structure of the dome completed just enough where engineers were able to rotate the dome’s skeleton for the first time.

ESO released a timelapse video this week of the dome’s movement, sped up from the actual snail’s pace of 1 centimeter per second. When the telescope is completed – currently set for sometime in 2028 — the rotation of the dome will allow the telescope to track objects in the night sky over the Chilean Atacama desert. The final operating speed will be at pace of 5 kilometers per hour.

Take note of the size of the humans moving about on the video. They appear like tiny ants compared to the immense size of the aptly named ELT.

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The Biggest Telescope in the World is Half Built

This image, taken in late June 2023, shows a night view of the construction site of ESO’s Extremely Large Telescope at Cerro Armazones, in Chile's Atacama Desert. Credit: ESO.

The European Southern Observatory continues to build the largest telescope in the world, the Extremely Large Telescope (ELT). Construction of the telescope began in 2014 with flattening the top of a mountain named Cerro Armazones in Chile’s Atacama Desert.

ESO just announced that progress on construction has crossed the 50% mark.  The remaining work should take another five years. When it finally comes online in 2028, the telescope will have a 39-meter (128 ft) primary mirror of 798 hexagonal segments, making it the largest telescope in the world for visible and infrared light. The new telescope should help to answer some of the outstanding questions about our Universe, such as how the first stars and galaxies formed, and perhaps even be able to take direct images of extrasolar planets.  

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Many of the World’s Greatest Observatories Suffer from Some Light Pollution

Night sky in the African country of Namibia. (Credit: Fabio Falchi; Licence Type: Attribution (CC BY 4.0))

In a recent study published in the Monthly Notices of the Royal Astronomical Society, an international team of researchers examined the levels of light pollution at astronomical observatories from around the world to better understand how artificial light is impacting night sky observations in hopes of taking steps to reduce it. But how important is it to preserve the scientific productivity of astronomical observatories from the dangers of light pollution, as noted in the study’s opening statement?

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Arecibo Won’t Be Rebuilt

Damage to the 305-meter telescope at Arecibo Observatory, after its collapse on Dec. 1, 2020. The remains of the instrument platform are visible on the telescope’s dish. Credit: NSF.

The National Science Foundation announced last week that it won’t rebuild or replace the iconic Arecibo Observatory in Puerto Rico, which collapsed in 2020. Instead, the NSF says they have solicited calls for proposals to build a multidisciplinary educational center at the site.

Additionally, the plans do not appear to allow for any future science or observing from the other facilities at the Arecibo site, as the NSF said they will not provide any “operational support for current scientific infrastructure, such as the 12-meter radio telescope or Lidar facility,” also on location.

The announcement has been met with disappointment and disbelief.  

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Astronomers Watched a “Near-Sun” Comet Disintegrate as it Flew too Close to the Sun

Near-Sun object 323P/SOHO observed by the Subaru Telescope on December 21, 2020 (left) and CFHT on February 11, 2021 (right). 323P/SOHO on its way to perihelion is seen as a point source in the center of the left image; after the perihelion, the comet has developed a long narrow tail as seen in the right image. (Credit: Subaru Telescope/CFHT/Man-To Hui/David Tholen)

Comets that venture close to the Sun can transform into something beautiful, but sometimes they encounter incineration if they get too close. Of the various types of comets that orbit close to the Sun, astronomers had never seen the destruction of the type classified as “near-Sun” comets. But thanks to a variety of telescopes on summit of Mauna Kea in Hawai?i, scientists have now captured images of a periodic rocky near-Sun comet breaking apart. They say the disintegration of this comet could help explain the scarcity of such periodic near-Sun comets.

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Here are All of Hubble’s Observations in One Picture

All of the Hubble Space Telescope's observations from the past 32 years, shown in one graphic. Credit and copyright: Casey Handmer. Used by permission.

Over the past 32 years, Hubble has made about 1.4 million observations of our Universe. Physicist Casey Handmer was curious how much of the sky has been imaged by Hubble, and figured out how to map out all of Hubble’s observations into one big picture of the sky.

It’s a gorgeous, almost poetic look at Hubble’s collective view of the cosmos. So, how much of the sky has Hubble imaged? The answer might surprise you.

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The Carina Nebula. Seen With and Without Adaptive Optics

This image shows a comparison of the new image (top) of the western wall of the Carina Nebula taken by the international Gemini Observatory, a Program of NSF’s NOIRLab, and an image of the same region without Adaptive Optics (bottom). The top image was taken with the Gemini South telescope with the GSAOI instrument using the GeMS adaptive optics system, and the bottom image was taken at the Cerro Tololo Inter-American Observatory with the Víctor M. Blanco 4-meter Telescope using the NEWFIRM instrument. Image Credit: International Gemini Observatory/CTIO/NOIRLab/NSF/AURA

Ever wonder how modern astronomical observatories take such clear images of distant objects? Advances in mirror design have allowed for larger and larger primary mirrors. But adaptive optics play a huge role, too.

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Climate Change is Making the Atmosphere Worse for Astronomy

climate change and observatories
Global climate change's effects will reach right up the skies, affecting such places as the VLTI in Chile. Courtesy ESO.

Modern astronomical telescopes are extraordinarly powerful. And we keep making them more powerful. With telescopes like the Extremely Large Telescope and the Giant Magellan Telescope seeing first light in the coming years, our astronomical observing power will be greater than ever.

But a new commentary says that climate change could limit the power of our astronomical observatories.

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