Timeline related to Greek Astronomy

6 April 648 BC

Archilochus of Paros (Αρχίλοχος ο Πάριος) a Greek poet describes a solar eclipse

Nothing there is beyond hope
nothing can be sworn impossible
nothing wonderful.
Since Zeus father of Olympians
made night from mid-day
hiding the light of the shinning-sun
and sore fear upon man.

Poem in Greek and German translation

In Honor: Asteroid or Minor Planet 5873 Archilochos 1989 SB3, discovered 1989 September 26 by E. W. Elst at La Silla.

About 600 BC

Pherekydes of Syros (Φερεκύδης ο Σύριος), the teacher of Pythagoras, performed astronomical measurements with a heliotropion device in the island of Syros. (Herodotus describes later that the Greeks learned to use the Gnomon and Polos from the Egyptians and also the division of the day in 12 parts.)

Thales of Miletus (Θαλής ο Μιλήσιος ) observed that the so-called Big Dipper constellation never dips below the horizon in Greece, but it does when viewed from Egypt.

Thales of Miletus (636-546) BC predicts a solar eclipse ( (28.5. 585 BC, Julian Calendar or 22. 5. 584 BC Gregorian Calendar Famous Eclipse )

About 560 BC?

Anaximander of Miletus (Αναξίμανδρος ο Μιλήσιος ) a student of Thales and according to Laertius the discoverer of the gnomon proposes that the Earth surface is cylindrical.

The moon, he said, had a borrowed light, and borrowed it from the sun; and the sun he affirmed to be not less than the earth, and the purest possible fire, D. Laertius.”

(Anaximander's Cosmos )author of the first geometrical model of the world...Charles Kahn Anaximander and the Origins of Greek Cosmology

About 536 BC

Cleostratus of Tenedos (Κλεόστρατος ο Τενέδιος), Octaetris (8 years period) to match the solar and lunar period, Constellations.

About 530 BC

Pythagoras of Samos (Πυθαγόρας ο Σάμιος ) gives the name cosmos to the universe.

About 500 BC

Heraclitus of Ephesus (Ηράκλειτος ο Εφέσιος) says the Universe is 10800 years old. In 1766 Georges Buffon said that the Earth is older than 6000 years (from fossils).

5th century

Diogenes of Apollonia (Διογένης ο Απολλωνιάτης) was the first to suggest that meteorites come from space (a realization that was subsequently forgotten for the next 2,000 years). (A class of meteorites are called in honour diogenites ) He made astronomic observation from Crete, a mountain in Apollonia (known also as Eleutherna)

490 BC

9th September 490 BC, date of the full moon that according to the Spartans prohibited them to help Athenians against the Persians in the battle of Maratarathon but it could be one month earlier according to new studies

About 470 BC

Parmenides (Παρμενίδης ο Ελεάτης) says that the Earth shape is spherical (Diogenes Laertius)

Harpalus, Astronomer (?-460) BC

About 450 BC
Anaxagoras (Αναξαγόρας ο Κλαζομενεύς) (500-428) BC taught that the moon shines with the light of the Sun (a hot red stone larger than Peloponese) and so was able to explain the eclipses.

Anaxagoras, in agreement with the mathematicians, held that the moon's obscurations (phases), month by month, were due to its following the course of the sun by which it is illuminated, and that the eclipses of the moon were caused by its falling within the shadow of the earth, which then comes beween the sun and the moon, while the eclipses of the sun where due to the interposition of the moon. Aetius

Oenopides (Οινοπίδης ο Χίος) (500-432) BC measured the inclination of the Earth axis with respect to the ecliptic plane to be 24 degrees, defined the Great Year to be about 59 years, the interval with an exact repetition of days in a year and the lunar cycle with the Sun and Moon in the exact same locations in the sky, accounting not just for months but also its inclination.

It is supposed that Pythagoras made the first discovery of the obliquity of the zodiac, but one Oenopides of Chios challenges to himself the invention of it. Plutarch

450-385 BC

Philolaus (Φιλόλαος) of Croton, in southern Italy, (c. 470 - c. 385) BC was the precursor of Copernicus in moving the earth from the center of the cosmos and making it a planet, but in Philolaus' system it does not orbit the sun but rather the central fire. Some scholars regard the astronomical system as a significant attempt to try to explain the phenomena, but others see it as primarily of mythic and religious significance. Philolaus is the first to incorporate all five planets commonly known in antiquity into an astronomical scheme in the correct order, which indicates that he was aware of the most up-to-date astronomical data. (Stanford Encyclopedia of Philosophy)

The cosmos according to Pythagoreans. The earth orbits around a central fire. The Anti-Earth is not visible like the central fire because Greece is on the opposite side on the earth

About 440 BC
Leucippus of Miletus (Λεύκιππος ο Μιλήσιος) said that the world consisted in the void and atoms, which are imperceptible individual particles that differ only in size, shape, and position. That these particles were imperceptible meant they met Parmenides' objection to the Pythagorean's geometric points and, since they alone were unchanging, change could be explained as mere sense impressions. "It is scarcely an exaggeration to say that even in 1900 the only new idea to Leucippus's theory was that each chemical element was identified with a separate atomic species" (Park 1990:41).

(? - 432)BC Meton of Athens (Μέτων ο Αθηναίος ), Astronomer and Geometer, introduced in Enneadecaterides the 19-year "Metonic” cycle (19 years or 235 lunations or 6940 days) , construction of a sundial

He appears in one comedy of Aristophanes, The birds (considered that he worked on squaring the circle problem):
PITHETAERUS In the name of the gods, who are you?
METON Who am I? Meton, known throughout Greece and at Colonus.
PITHETAERUS What are these things?
METON Tools for measuring the air. In truth, the spaces in the air have precisely the form of a furnace. With this bent ruler I draw a line from top to bottom; from one of its points I describe a circle with the compass. Do you understand?
PITHETAERUS Not in the least.
METON With the straight ruler I set to work to inscribe a square within this circle; in its centre will be the market-place, into which all the straight streets will lead, converging to this centre like a star, which, although only orbicular, sends forth its rays in a straight line from all sides.

About 420 BC

Democritus of Abdera (Δημόκριτος ο Αβδηρίτης) developed Leucippus's atomic theory: Atoms vibrate when hitched together in solid bodies and exist in a space which is infinite in extent and in which each star is a sun and has its own world. He also produced two major concepts in the history of ideas concerning the brain--that thought was situated there and, anticipating the nervous system, that psychic atoms constituted the material basis of its communication with the rest of the body and the world outside. Socrates, and hence the Platonic school, followed Democritus in locating thought in the brain.

Helicon (Ελικών ο Κυζικηνός ), Astronomer (?-400) BC

4th century BC

Hicetas of Syracuse (lκέτας ο Συρακούσιος) explains apparent motion of the fixed stars by the Earth spinning on its own axis.

Archytas of Tarentum (Αρχύτας ο Ταραντίνος) (428-350 BC) with a simple “Gedankenexperiment” assumes that the Universe is infinite.

After about 380 BC

Plato (Πλάτων ο Αθηναίος) said, in the Timaeus, that "as being is to becoming, so is truth to belief" (Plato 1929:29c). In other words, we can only believe, not know, on the basis of experience. Like, Parmenides, he held being and truth, indeed the world, to be timeless and unchanging, an ideal of which man can only hold the idea. This permitted him a certain amount of flexibility: He was willing to accept objections to his view of the universe, for example, if the new hypothesis would provide a rational explanation or 'save the appearance' presented by the planets. The five regular polygons he ascribed to the four elements plus the "decoration" of the universe (Plato 1929:55c), probably the animals of the zodiac.

372 BC

Ephorus of Cyme (c. 400-330 BC), of Cyme in Aeolia, Asia Minor, a student of Isocrates, observed a splitting of a comet

Remarkably, most sungrazing comets appear to be fragments of a single giant comet that broke apart near perihelion (closest approach to the Sun) long ago. Marsden speculates that the parent might have been a bright comet seen by the Greek astronomer Ephorus in 372 BC. Ephorus reported that the comet split in two. Splits may have occurred again and again, producing the Kreutz sungrazer family (named after the nineteenth-century German astronomer who studied them in some detail). The sungrazers share an elliptical orbit that brings some of the fragments less than 50,000 km from the Sun. Comet Champion of the Solar System

About 370-360 BC
Eudoxus of Cnidus (Εύδοξος ο Κνίδιος) invented a model of twenty-seven concentric spheres by which he was able to calculate the sun's annual motions through the zodiac, the moon's motion including its wobble, and the planets' retrograde motion. (27 Spheres, 1 for the fixed stars, 3 each for the Sun and Moon and 4 each for the 5 known planets of antiquity).
Heraclides of Pontus (390-322) BC says that Mercury and Venus rotate around the Sun. Earth rotates around its axis and is the center of the Universe. The Homocentric Spheres of Eudoxus.

Έκφαντος φησί την γην κινείσθαι περί το αυτής κέντρον ως προς Ανατολήν (DK 51A1 ) (DK 51A5) ... και Έκφαντος κινούσι την γην, ου μην γε μεταβατικώς αλλά τρεπτικώς ... από δυσμών προς ανατολάς περί το ίδιον αυτής κέντρον ενηξενισμένην.

Heraclides of Pontus and Ecphantus the Pythagorean make the earth move, not in the sense of translation, but by way of turning as on a axle, like a wheel, from west to east, about its own centre. Heath

About 335 BC

Aristotle (Αριστοτέλης ο Σταγειρίτης) settles in Athens, founds Lyceum. At the same time, Aristotle often states both his observations and his reasons with rather too much conviction: "The shape of the heaven is of necessity spherical; for that is the shape most appropriate to its substance and also by nature primary" (Aristotle 1930:286b). "A heavenly essence could not, according to [his] physics, manifest any but its own 'natural' movement, and its only natural movement [so his reason informed him] was a uniform rotation around the center of the universe" (Duhem 1908:15). His name for the heavenly essence, the quintessence, is aiqhr, of which the Latin cognate is 'aether' (Although Aristotle is perhaps the earliest theorist of aiqhr, he was not the first to use the word, e.g., Heraclitus used it to mean heavenly fire.)

About 330 BC
Heraclides of Pontus (Ηρακλείδης ο Ποντικός ) said that the earth turns daily on its axis "while the heavenly things were at rest..., considered the cosmos to be infinite..., [and] with the Pythagoreans, considered each planet to be a world with an earth-like body and with an atmosphere" (Dreyer 1906:123-125). He also suggested that Mercury and Venus have the sun at the center of their spheres.

Autolycus of Pitane (360-290) BC defined uniform motion as being when "a point is said to be moved with equal movement when it traverses equal and similar quantities in equal times" (Clagett 1959:164). Autolycus of Pitane writes On the Moving Sphere which studies the geometry of the sphere. It is written as an astronomy text.

Callipus of Cyzicus, Astronomer (c. 370- 310/300 BC) extended the model of Eudoxus Biography (Callipic Period “76 years or 940 lunations” or 27759 days)

About 325 BC
Pytheas (Πυθέας ο Μασσαλιώτης), tides are caused by moon.

Theophrastos (Θεόφραστος ο Ερέσιος) discovers the Sunspots (observed also independently and much earlier in China) Great Moments in the History of Solar Physics

About 310-260 BC
Aristarchus of Samos (Αρίσταρχος ο Σάμιος) (310-230) BC, in On the Sizes and Distances of the Sun and Moon, used trigonometry to estimate the size of the Moon and its distance by the Earth's shadow during a lunar eclipse. He was attacked by philosopher's such as the stoic Cleanthes who considered Aristarchus as an atheist (some similarity with the catholic church and Galileo)

Archimedes and others said that he maintained that the Moon revolved around the Earth and the Earth around the Sun which remained stationary like the stars.

Archimedes was the first to give an upper and lower values for the solar diameter (Solar Oblateness from Archimedes to Dicke) (PDF File)

Aristillus of Samos (Αρίστυλλος ο Σάμιος) and Timocharis of Alexandria (Τιμοχάρης ο Αλεξανδρεύς) (c. 300) BC, Astronomers prepared the first true star catalog (used later by Hipparchus to compare the recorded positions from his own measurements)

Conon of Samos (Κόνων ο Σάμιος) ( c. 260 BC – 220 ), Astronomer, solar eclipses observations

About 280-260 BC

Aratus Solensis (Αρατος ο Σολεύς)(c. 315/310 – 245/240 BC) poet (and scientist) born in Soli/Cyprus died in Pella, Φαινόμενα και Διοσημεία (The Phaenomena ) (1154 hexameters) . Probably the first scientific poem.

Aratus Phaenomena in Greek

Aratus, the poet of the heavens, will be read, said Ovid, as long as the sun and moon shall shine. S. Rappoport, History of Egypt

Written in the Stars Poetry and Philosophy in the Phaenomena of Aratus

About 240 BC
Eratosthenes of Cyrene (Ερατοσθένης ο Κυρηναίος) calculated the diameter of the earth by measuring noontime shadows at sites 800 km. apart. Assuming the earth is a sphere, the measured angle between the sites is seven degrees and the circumference is about 50 times 800 km, or about 40000 km.

Before the end of the third century BC
Astrolabes were in use for taking the angular distance between any two objects, usually the elevation in the sky of planets.

About 225-210 BC?
Apollonius of Perga (Απολλώνιος ο Περγαίος) writes Conics. He introduced probably first the terms 'parabola' and 'hyperbola,' curves formed when a plane intersects a conic section, and 'ellipse,' a closed curve formed when a plane intersects a cone.

Epigenes (Επιγένης ο Βυζάντιος) Astronomer (?-200 BC)

About 150 BC
Hypsicles (Υψικλής ο Αλεξανδρεύς) writes On the Ascension of Stars. In this work he is the first to divide the Zodiac into 360 degrees.

Seleucus of Seleucia (Σέλευκος ο Σελεύκειος) accepts Aristarchus Heliocentric model

About 134-127 BC

Hipparchus of Rhodes (Ιππαρχος ο Ρόδιος) measured the year with great accuracy and built the first comprehensive star chart with 850 stars and a luminosity, or brightness, scale. He is credited with the discovery of the precision of the equinoxes, and seems to have been very impressed that either of two geometrically constructed hypotheses could 'save the appearance' of the path that a planet follows: One shows the planets moving in eccentric circles and the other moving in epicycles carried by concentric circles (Duhem 1908:8).

Hipparchus cycle (304 years or 3760 lunations, less a day, or 111035 days)

Between 130 and 10 BC

Birth of Geminus of Rhodes (Γέμινος ο Ρόδιος) Astronomer, Mathematician, Introduction to Astronomy (Phenomena) PDF File . Geminus writes that the Earth is a sphere, the sun and the stars are spheres of fire from the same material, there are infinite number of stars, the Moon receives its light from the Sun.

In the first half of the first century BC
Titus Lucretius Carus, writing in Latin, set forth the teachings of the Epicurean school in De rerum natura. There he held that "the soul is itself material and so closely associated with the body that whatever affects one affects the other. Consciousness ends with death. There is no immortality of the soul. The universe came into being through the working of natural laws in the combining of atoms" (Columbia Desk Encyclopedia 1975:1626). This view is supported by the force of the wind which is the result of the impact of innumerable atoms.

46 BC
Sosigenes of Alexandria (Σωσιγένης o Αλεξανδρεύς) (?-46) BC designed a calendar of 365.25 days which was introduced by Julius Caesar.

92 AD

Agrippa observed in 92 AD an eclipse of Pleiades by the Moon.

About 100[?]
Plutarch (Πλούταρχος) (46-120 AD), in On the Face That Can Be Seen in the Lunar Disk, compared the Moon to the Earth, upheld the idea of the plurality of worlds, and tried to overturn Aristotle's theory of 'natural places' (Duhem 1985:479). Although he was surprised by the Moon's apparent lack of clouds that could be a result of the lack of water he considered that the dark areas probably to be seas. This was the reason of naming such a dark areas as a mare (sea).

St. Dionysius the Aeropagite, Astronomer (9-120 AD)

Cleomedes (Κλεομήδης) On the Circular Motions of the Celestial Bodies. .

About 110
Menelaus of Alexandria writes Sphaerica which deals with spherical triangles and their application to astronomy.

Between 127 and 141

Claudius Ptolemaeus (Πτολεμαίος Κλαύδιος) (87-158), better known as Ptolemy, put together a thirteen volume compendium of opinion and data concerning the stars, including the Mesopotamian eclipse record. In this book, the Almagest, Ptolemy rejected the Peripatetic physics of the heavens, using circles rather than spheres. He did so in order to simplify his calculations, judging the circles to be only models devised for the purpose of calculation and recognizing that the actual movements were unknowable. The Almagest also contains errors which were not corrected until the sixteenth and seventeenth centuries: e.g., saying that the earth is the center of the universe, the planets have circular, if eccentric, orbits, and the earth does not move--because the centrifugal force would cause anything even temporarily disconnected to lag behind. On the other hand, the tables of the planet's positions were of such accuracy that Nicholas Copernicus computed most of his numbers from them.

Theon of Smyrna (Θέων ο Σμυρναίος) (70-135) observations of Mercury and Venus between 127 and 132

About 160

The first Science Fiction Story by Lucian of Samosata that described kidnapping by extraterrestrials, star wars, trip to the moon! In the story Menippus meets Endymion who explains that he was kidnapped and brought to the moon while he slept. He adds that he is about to make war on the People of the Sun, whose King Phaethon has refused to allow him to colonize Venus. In the titanic struggle which follows, the People of the Sun are at last victorious and the triumphant Phaethon builds a high wall which prevents the light from his domain from reaching the moon, thus causing a total eclipse....

About 200 AD ?

Cleomedes (Κλεομήδης) On the Circular Motions of the Celestial Bodies. Great uncertainty about his life. Some say he was active around 370 AD

About 301
Iamblichus (Ιάμβλιχος) writes on astrology and mysticism. His Life of Pythagoras is a fascinating account.


Theon of Alexandria (Θέων ο Αλεξανδρεύς) (?-380) AD, Astronomer


Theophilus (Θεόφιλος ο Εδεσσαίος)(?-412) AD, Astronomer

Proclus Diadochus (Πρόκλος) (410-485)AD Mathematician, Astronomer, Philosopher


Ancient Greek astronomical texts , Preliminary version

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