Researchers in Egypt have uncovered a copy of the oldest known chart of visible stars, an endeavor undertaken by a 2nd Century BCE scientist known as the “father of scientific astronomy,” which was erased by ancient scribes so the parchment could be reused, LiveScience reports.

Hipparchus, an ancient Greek scientist, was the first known person to try to catalog the vastness of space as visible from a Greek island, making notes about the position and features of the lights in the sky that previous observers had bestowed with mystical powers.

Researchers examined a manuscript known as the Codex Climaci Rescriptus, a 6th Century AD Christian Palestinian Aramaic of the Old and New Testaments.  The manuscript is what’s known as a  palimpsest:  a text written on a “recycled” piece of parchment that had its original writing scraped away.  Shining various wavelengths of light on the parchment, researchers were able to uncover the original text, a copy of Hipparchus’s star chart.

Hipparchus (190 BCE to 120 BCE) moved to the island of Rhodes to make his scientific observations, which resulted in some of the earliest calculations of the movement of the moon and Sun.  He also created the first known scale against which one measure the brightness of stars.  He may have also observed a star exploding:  he noted that a star suddenly appeared in a previously empty part of the sky.

While Hipparchus’s written records have been long lost, the legend of his work was documented by later scientists and historians.  Pliny the Elder, a First Century AD Roman scientist, referred to Hipparchus’s work in his writings.

“I was very excited from the beginning,” the study’s lead researcher, Victor Gysembergh, a science historian at the French National Center for Scientific Research said in an interview. “It was immediately clear we had star coordinates.”