The synchrotron uses X-rays from agitated electrons to literally shed light on erased text from an ancient palimpsest manuscript. But part of Hipparchus’ catalog that would have been invisible on one of these palimpsests was revealed using multispectral imaging. Despite that fragility, using a synchrotron made it possible to decode traces of star coordinates on the palimpsest. Because the ink used to transcribe Hipparchus' star map was high in calcium, the synchrotron could see it. What has surfaced from Hipparchus’ star catalog can now be used to infer how ancient astronomers without telescopes were able to map the cosmos so precisely.