Assertion: proper motion | /r/HasProperty | suspected by early astronomers
Facets:
value: according to macrobius
type: OTHER
Source sentences:
text: Proper motion was suspected by early astronomers (according to Macrobius, AD 400) but a proof was not provided until 1718 by Edmund Halley, who noticed that Sirius, Arcturus and Aldebaran were over half a degree away from the positions charted by the ancient Greek astronomer Hipparchus roughly 1850 years earlier.