<P> 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 . </P>
<P> 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 . </P>
who discovered the first known instance of proper motion
who discovered the first known instance of proper motion
Edmund Halley
Edmund Halley