SLAC scientists use X-rays to search for the world’s oldest star map

At SLAC National Accelerator Laboratory in Menlo Park on Wednesday morning, researchers focused a powerful X-ray machine on pages of parchment from a medieval desert monastery, looking to reveal hidden traces of the world’s oldest star map.

The catalogue of stars was created more than 2,100 years ago by the Greek astronomer Hipparchus. Known only by mentions from other scientists of antiquity such as Pliny the Elder in the first century, scholars say it described more than 800 celestial...