10 Aug 2026-------------- Noirlab 2620

 

The new DESI Legacy Imaging Surveys map serves as the foundation for the largest-ever 3D map of the Universe, used to investigate dark energy

 

The newest DESI Legacy Imaging Surveys map, 13 years in the making, covers three-quarters of the sky and catalogs nearly four billion objects. This treasure trove is available to all and contains stars, galaxies, supernovae, gravitational lenses, and much more. Two NSF NOIRLab facilities contributed data to the map: the U.S. National Science Foundation (NSF) Mayall telescope and the NSF Blanco telescope, equipped with the U.S. Department of Energy-fabricated DECam.

Hold on to your telescopes: the DESI Legacy Imaging Surveys team has released the largest-ever 2D map of the Universe. The 5.6-trillion-pixel map contains nearly four billion celestial objects, including stars, galaxies, black holes, and asteroids. The data are available for all to use and are publicly viewable through the Legacy Survey Sky Viewer.

Astronomers and citizen scientists can combine the map with their own observations to better understand our Universe. Researchers can search for rare phenomena like gravitational lenses, observe fleeting events like supernovae, and investigate two of physics’ biggest mysteries: dark matter, the invisible substance that accounts for most of the mass in our Universe, and dark energy, the force driving our Universe’s accelerating expansion. 

The new map builds on earlier versions from the DESI Legacy Imaging Surveys that have already proved invaluable. To date, more than 1800 science papers have been published referencing the Legacy Surveys’ data.

“It’s part of the fabric of astronomy research now,” says David Schlegel, a co-lead of the Legacy Surveys and scientist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). “When you're working with astronomical objects today, you often start by pulling up the Legacy Imaging Viewer to see what you’re looking at.” 

Covering roughly 75% of the sky in visible and near-infrared light, the updated map provides a deep view of the extragalactic Universe not blocked by the dust and stars of our own Milky Way. Researchers expect it will remain the most comprehensive 2D map of our Universe for years to come. 

 

More than 160 scientists contributed to data collection for the project, and a team of 20 produced the final dataset released today. It was built by combining 263,407 telescope exposures from three ground-based sky surveys:

• The Dark Energy Camera Legacy Survey (DECaLS), conducted by the 570-megapixel Department of Energy-fabricated Dark Energy Camera (DECam), mounted on the U.S. National Science Foundation (NSF) Victor M. Blanco 4-meter Telescope at NSF Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab.
• The Mayall z-band Legacy Survey (MzLS), conducted by the NSF Nicholas U. Mayall 4-meter Telescope at NSF Kitt Peak National Observatory (KPNO), a Program of NSF NOIRLab.
• The Beijing-Arizona Sky Survey (BASS) at the University of Arizona’s Steward Observatory, conducted with the UA Bok 2.3-meter Telescope at KPNO and supplemented by years of data from NASA’s Wide-field Infrared Survey Explorer (WISE) satellite mission.

 

In addition to the extended file collection, the DESI Legacy Surveys’ full catalog of data is made available as a searchable database via the Astro Data Lab at the Community Science and Data Center (CSDC), a Program of NSF NOIRLab. These services are accessible to the entire astronomy community to facilitate data access and analysis.

“Explorations of our Universe always start with images of the night sky. The DESI Imaging Legacy Surveys are just one step in this venerable human tradition,” says Arjun Dey, co-lead of the Legacy Surveys and an astronomer at NSF NOIRLab. “For our team, these data are fundamental to the investigation of the expansion history of the Universe and the formation of our galaxy. But the skies belong to everyone, and this survey gives everyone the chance to marvel at their wonders.”

The DESI Legacy Imaging Surveys were originally conducted to prepare for the Dark Energy Spectroscopic Instrument (DESI) survey. The Legacy Surveys’ 2D map is essentially a deep photograph of the sky; it records where galaxies and stars appear and how bright they appear. This crucial step enables DESI to select objects and measure their light in different wavelengths to determine their distances, building the largest high-resolution 3D map ever made. Scientists use this map to study the way galaxies have clustered at different ages of the Universe to track dark energy over time.

In April 2026, DESI completed its original five-year survey ahead of schedule and with vastly more objects than expected. The early results have shown surprising hints that dark energy’s impact may be weakening over time — a paradigm shift that could potentially shape the predicted fate of our Universe. DESI expects to publish improved results using its first five years of data in 2027 and is continuing observations into 2028.

Beyond supporting DESI, the Legacy Surveys will be a foundational reference for the next generation of telescopes. As new observatories like NSF–DOE Vera C. Rubin Observatory, jointly funded by the NSF and DOE’s Office of Science (DOE/SC), and NASA’s Nancy Grace Roman Space Telescope come online, researchers can compare their observations with one of the deepest and most comprehensive views of the sky ever assembled.

The Legacy Surveys’ data will also help scientists train artificial intelligence tools to analyze petabytes of astronomical data and accelerate new discoveries. It will be among the datasets used in an astrophysics pilot project within the American Science Cloud, part of the DOE’s Genesis Mission.

 

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(B) Copeland Septet group of galaxies

(C) CTIO on the Edge of the World