Page "Astrometry" Paragraph 2

The history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements.

This can be dated back to Hipparchus, who around 190 BC used the catalogue of his predecessors Timocharis and Aristillus to discover the earth ’ s precession.

In doing so, he also developed the brightness scale still in use today.

Hipparchus compiled a catalogue with at least 850 stars and their positions.

Hipparchus's successor, Ptolemy, included a catalogue of 1, 022 stars in his work the Almagest, giving their location, coordinates, and brightness.