The 200-inch Hale Telescope, a masterpiece of engineering at Caltech's Palomar Observatory, was the world's largest telescope until 1993. Scott Kardel/Palomar Observatory/Courtesy of Palomar Observatory/California Institute of Technology hide caption

itoggle caption Scott Kardel/Palomar Observatory/Courtesy of Palomar Observatory/California Institute of Technology

This artist's illustration shows what NuSTAR should look like in orbit after its 30-foot-long mast deployed. JPL-Caltech/NASA hide caption

itoggle caption JPL-Caltech/NASA