Researchers have officially released the largest 2D color map of the universe to date. This project, led by teams at the Lawrence Berkeley National Laboratory and the DESI Legacy Imaging Surveys, brings together over 260,000 telescope exposures to create a visual record of almost 4 billion celestial objects.
The effort began thirteen years ago with the goal of tracking dark energy. To study such a phenomenon, physicists needed a way to map the locations of galaxies and stars across the observable sky. This 2D map serves as a critical foundation for those 3D models. The team combined data from three distinct sky surveys: the Beijing-Arizona Sky Survey, the Dark Energy Camera Legacy Survey, and the Mayall z-band Legacy Survey.
More than 160 scientists contributed to the final product. Project co-lead David Schlegel noted that the map covers the entire extragalactic sky, which includes regions not obscured by the Milky Way. Dustin Lang, another key contributor, helped develop code that reconciles image quality across the vast dataset, allowing computers to predict the appearance of distant objects by comparing multiple exposures of the same sky regions.
The impact of this data goes beyond the initial research team. Since the project started, various iterations of the data have appeared in over 1,800 scientific papers. Undergraduate students at UC Berkeley have also used these findings to identify rare gravitational lensing systems, highlighting the role of this map in ongoing astronomical discoveries.
Schlegel reflects on the project as a successful long-term collaboration that started when he was a graduate student. He describes the daily use of this data by other researchers as a validation of the time and resources invested in the effort. The map is now available for the broader scientific community to access and apply toward their own studies of the universe.