The Age of Exploration: Chapter 5, Exercise 2 — Possible Solution
======================================================================

CORRECTION
The source says Hypatia did not invent the astrolabe: she taught its
construction to her student Synesius. The instrument emerged from the
Hellenistic period as a two-dimensional adaptation of the armillary sphere,
and predates Theon of Alexandria (about 335 to 405), who wrote a treatise on
it.

REWRITE
"The astrolabe emerged in the Hellenistic period; Hypatia taught its
construction but did not invent it."