With wide fields of view, Dragonfly’s telephoto lenses have spotted sprawling, faint galaxies that lack stars. PIETER VAN DOKKUM

Improving on a Dutch invention, Galileo Galilei in 1609 used glass lenses to build the first telescope capable of studying the night sky. But soon after Isaac Newton constructed the first reflecting telescope later that century, mirrors took over: Astronomy today is dominated by telescopes with giant mirrors up to 10 meters wide.

Galileo’s approach has made a comeback with Dragonfly, a telescope in New Mexico built from two fly-eye arrays of 24 Canon telephoto lenses. This month, the Dragonfly team announced it would add 120 more of the lenses in a $3.65 million upgrade, which will make it the largest lens-based telescope in the world in terms of light-gathering power.

With a field of view far greater than that of an equivalent reflecting telescope, Dragonfly promises to capture the dim glow of vast, tenuous gas clouds that hold clues to the universe’s unseen dark matter. “Dragonfly is going to provide a completely new view of the universe,” says team member Deborah Lokhorst of the University of Toronto (UT).

Large telescope mirrors excel at gathering photons from the distant universe and zooming in on particular objects with sharp resolution. But they tend to have small fields of view, and scattered starlight from internal reflections can swamp the faint signals from extended structures like diffuse nebulae.