How did John Flamsteed encourage Edmond Halley to study astronomy?

Edmond Halley was introduced to John Flamsteed by letter while Halley was a student at Queen’s College, Oxford. During visits to the Royal Greenwich Observatory, where Flamsteed served as the first astronomer royal, Flamsteed encouraged Halley to pursue the study of astronomy.1

Halley was particularly influenced by Flamsteed’s project of using the telescope to compile an accurate star catalog of the northern sky. This inspiration led Halley to propose a similar endeavor for the Southern Hemisphere, resulting in his expedition to St. Helena in 1676 to record the positions of southern stars.1