Hubble is drawing the treasure map that the Roman telescope will follow

Gravitational lenses are nature's magnifying glasses: a massive galaxy bends the light of something far behind it, letting astronomers study both the distant object and the invisible dark matter doing the bending. The Hubble Space Telescope can examine these lenses one at a time, in exquisite detail. Its successor, the Roman Space Telescope, will see them by the thousands — far too many to study without a plan. So astronomers are using Hubble's sharpest lens images now to build the computer models Roman will need, turning one telescope's patience into the next telescope's speed.