Sosigenes of Alexandria
Sosigenes of Alexandria was an astronomer in the 1st century BC. Julius Caesar consulted him, and other astrologers, before introducing the Julian calendar. Sosigenes also influenced Caesar's writing "De astris", but only parts of it remain. Pliny the Elder wrote In his Natural History that Sosigenes observed that the planet Mercury never had an elongation angle greater than 22 degrees from the sun.