Below is a rough timeline for the main developments in ancient Greek astronomy presented without supporting evidence. For more detail, including discussion and sources, please read the relevant parts of the astronomers section or, when developed, the history and special topics sections.
c. 3000 – c. 1100 BCE Cycladic, Minoan and, latterly, the Hittite and Mycenaean civilisations. Aegean seafarers use the northern circumpolar constellations (in modern terms: Ursa Major, Ursa Minor, Draco) in order to navigate at night, thereby enabling trade across the eastern Mediterranean. The north celestial pole (known simply as a reliable fixed point) is marked by the star Thuban (α Draconis), whose closest approach (declination 89º 52') was in 2786 BCE and which remained within 10º of the pole throughout the Minoan and Mycenaean eras.
c. 1100 – c. 800 BCE The Greek dark ages and the disintegration of the Hittite empire into separate kingdoms. Early Mediterranean astronomical knowledge is largely inherited and developed by Levantine/Phoenician seafarers who begin to explore westwards, ultimately reaching the Atlantic coast of Spain. As Thuban moves away from the pole, the constellation of Ursa Minor moves closer to it and, in conjunction with the more distant Ursa Major, becomes a better guide.
c. 750 BCE Greek civilisation reboots with growing material and cultural prosperity. The Homeric poems, the Iliad and the Odyssey, coalesce into something like their final forms, revealing the basic nature of Greek astronomy in this era. A few noticeable asterisms and constellations such as Orion, the Pleiades, Boötes and the Bear/Wagon (Ursa Major) are mentioned. Sailing at night by the stars resumes (if indeed it ever stopped completely), as illustrated by Odysseus sailing eastwards by keeping Ursa Major to his left.
c. 700 BCE Hesiod writes two poems, Theogony and Works and Days. The first details a mythological conception of the origin of the gods and the world. The second reveals a night sky which is essentially the same as that in Homer (with the addition of Sirius), but described in relation to a farming calendar which is synchronised with the risings, settings and culminations of certain stars and constellations.
624 BCE. Greek Ionia and neighbouring non-Greek Lydia are booming. Birth of Thales of Miletos who in Greek tradition becomes the first philosopher and scientist. He introduces to the Greeks the Phoenician practice of using Ursa Minor for navigation. He foretells (in some unspecified way) a solar eclipse now identified as that of 28th May 585 BCE, an achievement which is probably the result of him noticing a fortuitous pattern of eclipses rather than through the appropriation of Mesopotamian data and methods.
610 BCE. Birth of Anaximander of Miletos, the first known person to present some kind of physical model of the whole cosmos. The Earth is conceived as an unsupported cylinder in the middle of the universe whose diameter is three times its height. The stars are located on a sphere around the Earth on rings whose distance from the Earth are nine times diameter of the Earth. The Moon is on a ring eighteen times its diameter and the Sun on a ring twenty-seven times its diameter. The rings were filled with fire and the celestial bodies themselves merely holes in the rings. He is also credited with introducing the gnomon into Greece.
586 BCE. Birth of Anaximenes of Miletos who states that the cosmos is filled with air and that all other substances and phenomena are condensations or rarefactions of it. The earth is flat, like a leaf floating on air, but the celestial bodies, which are fiery but also flat, do not travel under it after setting, but around it.
c. 575 BCE. Birth of Pythagoras of Samos.
c. 570 BCE. Birth of Xenophanes of Kolophon.
c. 546 BCE. Fall of Lydian capital Sardis to the Persians. Exodus of some prominent Greeks, such as Xenophanes, westwards to the prosperous Greek cities in Italy. Putative deaths of Thales and Anaximander.
c. 545 BCE. Birth of Herakleitos of Ephesos.
c. 520 BCE. Floruit of Kleostratos of Tenedos, a shadowy figure, who undertook meteorological and astronomical work. He observed the winter solstice and may have been responsible for devising the first form of the zodiac in Greece. If so, this was probably based on the still fluid Babylonian system and imported via Persian intermediaries.
c. 500 BCE. Birth of Anaxagoras of Klazomenai.
c. 490 BCE. Birth of Oinopides of Chios.
c. 450 BCE. Beginning of the idea that the Earth is (roughly) spherical in shape, probably due to Oinopides and his work on the ecliptic. Before this, almost everyone believed it to be flat. The change in opinion took several decades to accomplish with some notable holdouts (Demokritos, for example). By around 400 BCE, however, it seems that most people accepted that the Earth was a sphere.
432 BCE. Observation of the summer solstice in Athens by Meton and Euketemon. This occurred on 28th June at 10:26, but according to Ptolemy they determined it to be on 27th June at dawn, about 30 hours too early.
428 BCE. Birth of Plato.
384 BCE. Birth of Aristotle
357 BCE. Occultation of Mars by the Moon on 4th May, reported indirectly by Aristotle.
330 BCE. Start of the first Kallippic Cycle on the summer solstice (28th June) devised by Kallippos of Kyzikos. A refinement of the Metonic Cycle, it equated 76 years with 940 lunations.
295 BCE Timocharis of Alexandria carries out the first of a series of four known observations of lunar occultations.
273 BCE Calculated date around which Timocharis carried out twelve known star observations, probably as part of a project to create a star catalogue which was later used by Hipparchos and Ptolemy.
258 BCE. Calculated date around which Aristyllos of Alexandria, an associate of Timocharis, carried out six star observations, perhaps to complement the observations of the former.
c. 190 BCE. Birth of Hipparchos of Nicaea.
137 BCE. Calculated epoch of the equatorial observations by Hipparchos.
c 100 CE. Birth of Ptolemy.
138 CE. Epoch of Ptolemy's star catalogue.
c. 150 CE. Completion of Ptolemy's Almagest.
Last updated 12/05/2020
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