This issue of Photonics Focus explores the tools and systems that modern astronomers use to study space from the ground. Two feature articles explain different methods to create ever-larger telescope mirrors: spin-casting monoliths, and segmentation with adaptive optics. Another article reveals the enormous challenge of building highly precise instruments in some of the most seismically unstable locations on Earth; and yet another tells the story of the unfathomable amounts of data that will be generated by modern instruments, and how scientists plan to manage it.