He divided the stars that he could see into classes of apparent brightness. During about the 100s AD, Aristotle's and Hipparchus's theories were expanded upon by a man names Ptolemy. He was a Greek astronomer who live in Egypt. He published a book called the Almagest, in which he presented his ideas and summarized those of his predecessors. This work is our main source of knowledge of Greek astronomy.
Greek astronomers help form the foundation for modern astronomy.
Hipparchus's system of magnitude of brightness is still used today, although it is modified slightly. Some versions of his ideas and his table of planetary motions were accepted for nearly 1,500 years. Some of ancient Greece astronomer's theories were very influential, and many still stand today. This page has been visited times.