Credit: Robert Besuner/Berkeley Lab, DESI Collaboration
Crews at the Mayall Telescope near Tucson, Arizona, lift and install the top-end components for the Dark Energy Spectroscopic Instrument, or DESI. The components, which include a stack of six lenses and other structures or positioning and support, weigh about 12 tons. DESI, scheduled to begin its sky survey next year, is designed to produce the largest 3-D map of the universe and produce new clues about the nature of dark energy.