The DESI Legacy Imaging Surveys team published a 5.6-trillion-pixel atlas on August 10, 2026, marking the most comprehensive two-dimensional map of the universe ever assembled. This high-resolution dataset catalogs nearly 4 billion cosmic objects across 75 percent of the sky and is now available for public access via the Legacy Survey Sky Viewer.
Lawrence Berkeley National Laboratory and the National Science Foundation’s NOIRLab collaborated to produce this resource, which functions as active infrastructure rather than a static archive. The map has served as the primary targeting guide for the Dark Energy Spectroscopic Instrument since June 2026, ensuring the robotic fiber positioners on the Nicholas U. Mayall 4-meter telescope maintain operational efficiency.
This 2D imaging survey provides the essential spatial coordinates and brightness data that allow 3D spectroscopic instruments to function effectively. While the 2D map identifies where objects reside, the 3D spectroscopic survey measures the Doppler shift of light to determine precise distances, creating a complementary relationship between the two observational methods.
The project required the integration of 263,407 individual telescope exposures captured over 13 years from multiple global sources. These sources include the Dark Energy Camera at the Cerro Tololo Inter-American Observatory in Chile, the Nicholas U. Mayall 4-meter telescope in Arizona, the University of Arizona’s Steward Observatory, and NASA’s Wide-field Infrared Survey Explorer satellite.
Merging data from the Cerro Tololo Inter-American Observatory and the University of Arizona’s Steward Observatory presented significant technical hurdles regarding photometric calibration and atmospheric correction. Engineers had to normalize the sensitivity of the Dark Energy Camera against the specific optical characteristics of the Steward Observatory instruments, ensuring that a star measured in the southern hemisphere appeared with consistent brightness when compared to northern observations.
Engineers processed this massive volume of data using the Perlmutter supercomputer at the National Energy Research Scientific Computing Center. The system utilized 1,536 GPU-accelerated nodes to reconcile varying atmospheric conditions, photometric offsets, and astrometric solutions across the disparate source images over an eight-week continuous computation period.
The resulting catalog serves as a critical baseline for the Vera C. Rubin Observatory, which began its full sky survey on June 30, 2026. Researchers will cross-match incoming alerts from Rubin against this established catalog to identify transient phenomena, such as moving asteroids or changing stellar brightness, with greater accuracy.
NASA’s Nancy Grace Roman Space Telescope will also utilize this data for target identification and calibration following its scheduled launch on August 30, 2026. The U.S. Department of Energy has designated this dataset as a primary training resource for artificial intelligence classifiers under the Genesis Mission, further embedding the map into the future of automated astrophysical analysis.
The significance of this release lies in its role as a prerequisite for the ongoing investigation into dark energy. By providing the targeting catalog for the DESI spectrograph, the map enabled the measurement of tens of millions of galaxies, which recently yielded evidence suggesting that dark energy may be weakening over cosmic time.
This discovery challenges the long-standing Lambda-CDM standard model of cosmology, which relies on the assumption of a constant dark energy density. The expanded targeting catalog will now support the extended DESI program through 2028, allowing researchers to refine these findings and test the limits of current cosmological theories.
The scientific community anticipates that the full five-year dataset, supported by this 2D infrastructure, will provide the necessary resolution to clarify whether the observed weakening of cosmic acceleration is a fundamental shift in physics. Further analysis of this expanded survey data is expected to yield refined results in 2027, potentially reshaping the understanding of the universe’s expansion history. David Schlegel, co-lead of the Legacy Surveys and a scientist at Berkeley Lab, noted that the map has become part of the fabric of modern astronomy research, serving as the starting point for investigators examining specific astronomical objects.
