The Digital Press

The Milky Way Backup Program (MWBP) uses the DESI instrument to collect spectra from millions of stars, focusing on regions and brightness levels often missed by the main surveys. It efficiently gathers data during twilight and poor weather, significantly expanding our understanding of the Milky Way's stellar population.

Why it matters: MWBP enhances stellar data coverage by targeting stars beyond the main survey’s reach in brightness and location.

The big picture: The program complements DESI’s Main Survey, doubling stellar spectra while using less than 9% of observing time.

Stunning stat: By March 2025, MWBP obtained spectra for about 7 million stars, including 1.2 million released publicly.

The stakes: Expanding stellar data improves galactic models but depends on maximizing limited telescope time and variable conditions.