Kitt Peak National Observatory

A tessellated image of a white cap with a blue dot on the right edge, with shadow surrounding. This image is tessellated many times. A single cap, center right, is different: It has a white dot with a white concentric circle around it on top. No blue.

DESI will capture and study the light from tens of millions of galaxies and other distant objects to better understand our universe and the properties of dark energy. The formal start of DESI’s five-year survey follows a four-month trial run of its custom instrumentation that captured 4-million spectra of galaxies — more than the combined output of all previous spectroscopic surveys. Fermilab has contributed multiple components to the international collaboration led by Berkeley Lab.