After two decades of hard work, scientists and engineers at the U.S. Department of Energy's SLAC National Accelerator Laboratory and their collaborators are celebrating the completion of the Space-Time Legacy Survey (LSST) camera. Once installed on a telescope in Chile, the 32-megapixel LSST camera will help scientists better understand dark matter, dark energy, and other mysteries of our universe.
Researchers are examining LSST cameras. The camera will soon be shipped to Chile and become the centerpiece of the Vera-C. Rubin Observatory (right). Source: Greg Stewart/SLAC National Accelerator Laboratory
As the centerpiece of the Vera C. Rubin Observatory, funded by the Department of Energy and the U.S. National Science Foundation, the 32-megapixel camera will help researchers observe our universe in unprecedented detail. Over the course of a decade, it will generate a wealth of data on the night sky in the Southern Hemisphere, which researchers will mine to gain new insights into the universe. These data will help researchers understand the dark energy that drives the accelerating expansion of the universe, as well as the search for the mysterious substance that accounts for about 85% of the universe's matter - dark matter. The researchers also plan to use the Rubin data to better understand the changing night sky, the Milky Way, and our own solar system.
"With the one-of-a-kind LSST camera completed at SLAC and soon integrated with other systems at the Rubin Observatory in Chile, we will soon begin producing the greatest imagery and most informative map of the night sky ever created," said Željko Ivezić, director of construction at the Rubin Observatory and professor at the University of Washington. "
To achieve this, the SLAC team and its partners built the largest astronomical digital camera ever built. The camera, which is about the size of a small car, weighs about 3000 kilograms (3 metric tons), and has a front lens that is more than 5 feet wide, making it the largest lens ever made for this purpose. Another three-foot-wide lens had to be specially designed to maintain shape and optical clarity while also sealing the vacuum chamber that housed the camera's huge focal plane. The focal plane consists of 201 custom-designed CCD sensors, which are so flat that they vary no more than one-tenth the width of a human hair. The pixel itself is only 10 microns wide.
Built at the SLAC National Accelerator Laboratory, the LSST camera is the largest astronomical digital camera ever built. The camera is the centerpiece of the Vera-C-Rubin Observatory's 10-year Space-Time Heritage Survey (LSST), which will capture the entire southern sky every 3 nights. The camera's data will help address some of the most pressing questions in cosmology, such as the nature of dark energy and dark matter, as well as advance research into the solar system and the changing night sky. Photo credit: Olivier Bonin/SLAC National Accelerator Laboratory
Aaron Roodman, SLAC professor and deputy director of the Rubin Observatory and head of the camera project, said the camera's most important feature was its resolution, which is so high that it would take hundreds of ultra-high-definition TVs to display one of its images at full size. "Its images are so detailed that it can distinguish a golf ball 15 miles away, while covering a sky seven times wider than the full moon. These images, which contain billions of stars and galaxies, will help unravel the secrets of the universe."
Kathy Turner, program manager for the Department of Energy's Space Frontiers program, said it was increasingly important to reveal those secrets. "To expand our understanding of fundamental physics more than ever before, we have to look further afield into the universe," Turner said. With the LSST camera at its core, the Rubin Observatory will explore the universe deeper than ever before, helping to answer some of the hardest and most important questions in physics today. "
Now that the LSST camera has been completed and fully tested at the SLAC, it will be packaged and shipped to Chile and sent to the 8,900-foot-tall Cerro Pachón in the Andes Mountains, where it will be hoisted onto the Simone Survey Telescope later this year.
Once operational, the camera's primary purpose is to map the position of a large number of objects in the night sky and measure their brightness. Researchers can infer a wealth of information from this catalog. Perhaps most notably, the LSST camera will look for signs of weak gravitational lensing, in which massive galaxies subtly bend the light of the background galaxy to our path. Weak lenses reveal some of the distribution of mass in the universe and how mass changes over time, which will help cosmologists understand how dark energy drives the expansion of the universe.
Martin Nordby, senior engineer at SLAC and project manager for LSST cameras, said the observatory was the first to be built to study weak lenses of this scale, and the project prompted scientists and engineers to develop a number of new technologies, including new CCD sensors and some of the largest lenses ever built, and to ensure that all of these components work well together.
An artist's rendering of the LSST camera, showing its main components, including the lens, sensor array, and toolbox. Source: Chris Smith/SLAC National Accelerator Laboratory
Scientists also hope to study patterns in the distribution of galaxies and how these patterns change over time, identify dark matter populations and discover supernovae, all of which contribute to a better understanding of dark matter and dark energy.
What else can such a big camera do?
The same images revealing details of distant galaxies will help researchers study something closer to home: our own Milky Way. Many of the stars in the Milky Way are small and faint, but with the sensitivity of the LSST camera, researchers can hopefully create a more detailed map of the Milky Way, providing insight into the structure and evolution of the Milky Way, as well as the nature of the stars and other celestial bodies within it.
Closer to Earth, researchers hope to conduct a more thorough survey of the many small bodies in the solar system. According to estimates by the Rubin Observatory, the project could increase the number of known celestial bodies by a factor of 10, which could shed new light on how the solar system was formed, and perhaps help identify the threat posed by asteroids that are too close to Earth.
The camera will be mounted on the Simeone Survey telescope at the Rubin Observatory, which is located high in the Chilean Andes. Source: Rubin Observatory/National Science Foundation/AURA
Finally, Rubin scientists will study how the night sky changes – for example, how stars die or how matter falls into a supermassive black hole at the center of a galaxy.
SLAC Director John Sarrao said the camera was a "tremendous achievement" for the lab and its partners. The LSST camera and the Rubin Observatory will open a new window into our universe, giving us insight into some of the most mysterious things in the universe while revealing the wonders that are closer to us. "I am thrilled to see the center's scientific and technological expertise, project leadership, and strong global partnerships come together in such an impactful way. We can't wait to see what's next." "
Collaborative laboratories that offer expertise and technology include the Brookhaven National Laboratory, which manufactures digital sensor arrays for cameras, and the Lawrence Livermore National Laboratory, which designs and manufactures the lenses for the camera together with its industrial partners, and the National Institute of Nuclear and Particle Physics at the National Center for Scientific at the French National Centre for Scientific (IN2P3/CNRS). Research), which is involved in the design of sensors and electronics, and manufactures a filter exchange system for the camera, which will allow the camera to capture light in six different bands, from ultraviolet to infrared.
Front view of the completed LSST camera, showing the 32-megapixel focal plane. Photo credit: Jacqueline Ramseyer Orrell/SLAC National Accelerator Laboratory
Paul O'Connor, Senior Physicist in the Instrumentation Division at Brookhaven Laboratories, said: "The team at Brookhaven Laboratories, some of whom have been working on the project for over 20 years, are very pleased to see the completion of the LSST camera. The fast, ultra-sensitive CCD module we have developed with multiple collaborators will contribute to the Rubin Observatory's breakthrough scientific research over the next decade, and we look forward to collaborating on this flagship Astronomical Survey project." "
A major feature of the camera's optical components is its three lenses, one of which is 1.57 m (5.1 ft) in diameter and is believed to be the world's largest high-performance optical lens ever manufactured. Vincent Riot, an engineer at Lawrence Livermore National Laboratory and former LSST camera program manager, said, "Lawrence Livermore National Laboratory is honored to have the opportunity to design and oversee the manufacture of large lenses and optical filters for LSST cameras, including the largest lens in the world. LLNL was able to leverage the large-scale optical technology expertise it has accumulated over decades of developing the world's largest laser system, and we are thrilled to see this unprecedented instrument completed and ready to travel to the Rubin Observatory." "
Pierre Antilogus, an IN2P3/CNRS camera scientist, said: "In order to make a cosmic 3D film, the camera has to take an image in about 2 seconds and change the filter in 90 seconds. This is an amazing feat for a camera of this size. If the size of the focal plane of an LSST camera is unique, the density of its internal technology is even more impressive. By taking charge of the filter exchange system and the contribution of the focus plane, our team is excited to be part of the collective adventure of developing such a powerful camera. "
Travis Lange, deputy project manager and camera integration manager for the camera, said building the camera was also a meaningful challenge for the SLAC team that built the camera and led the project: "I'm very proud of what we've done. It's a very unique project that has exposed me to a lot of incredible experiences – who would have thought that the Secretary of State and the Speaker of the House would hold a press conference in front of the camera cleanroom? It would be a difficult project to catch up with."
编译自:ScitechDaily