SOCRATES: Shall we make astronomy the next study? What do you say?
GLAUCON: Certainly. A working knowledge of the seasons, months and years is beneficial to everyone, to commanders as well as to farmers and sailors.
SOCRATES: You make me smile, Glaucon. You are so afraid that the public will accuse you of recommending unprofitable studies. Plato, Republic VII
Important events in astronomical history
Spring equinox in Gemini.
Solstices and equinoxes determined.
Spring equinox in Taurus.
First maps made.
Majority of constellations named by sideronomists.
Emperor Yao founded Chinese calendar and punished astronomers who were drunk during eclipse.
Spring equinox in Aries.
Destruction of Cretan civilization.
Great Sun temple at Karnak finished.
Sundials and water clocks constructed.
Iknaton started monotheistic Sun worship, 1375.
Babylonian Boundary stones erected.
Exodus of the Israelites from Egypt.
Fall of Troy.
Zoroastrian religion founded.
Solomon's temple built.
Babylonians predicted eclipses by Saros; their astrology became personal.
First Olympiad, 776.
Rome founded, 753, (but not built in a day).
Thales eclipse, 585.
Pythagoras identified morning and evening star, and began scientific study of planetary motions.
Persian wars and age of Pericles.
Herodotus recited his history in Athens, 438.
Anaxagoras discovered that the Moon shone by reflected light, 435.
Plato born, 427.
Death of Socrates, 399.
Discovery of Earth as a planet.
Plato taught true direction of planetary motions.
Aristotle taught geocentric theory.
Pytheas of Marseilles visited Britain.
Philip of Macedon conquered Greece, 346.
Alexander the Great measured the route to India, and died there, 323.
Aristarchus of Samos suggested heliocentric theory, 260.
Aratus compiled poetic list of constellations, 240.
Eratosthenes introduced armillary sphere; measured obliquity of the ecliptic; wrote geography.
Hipparchus measured comparative distances of Sun and Moon; established astronomy and geography on geometric basis; discovered precession of the equinoxes; introduced astrolabes.
Spring equinox left constellation of Aries and entered Pisces, 140; Zodiacal signs differentiated from constellations.
Last year of Confusion, 46.
Julian calendar introduced, 45.
Strabo's geography published, 20.
Greatest conjunction of planets, 7.
Birth of Jesus Christ, 7.
Jesus was crucified, 33.
Ptolemy wrote on astronomy, geography and mathematics, 150.
Heretics and astronomers driven eastward.
Spherical Earth denounced as heretical, 320.
Modern Hindu chronology started.
Rome conquered by Visigoths, 410.
Very dark ages.
Dionysius Exiguus devised modern chronology from birth of Jesus Christ.
Flight of Mohammed from Mecca, 622.
Charlemagne crowned Emperor of the West, 800.
Alfred the Great founded Oxford University, 869.
Arabian astronomy flourished.
First Norse explorations.
Halley's comet and William the Conqueror; first Indian pueblo date, 1066.
Introduction of Arabic learning into Europe, 1077.
Omar Khayyam, Astronomer-poet of Persia, devised a calendar.
First and second crusades.
Compass introduced into Europe.
Growth of Universities.
Roger Bacon reintroduced theory of spherical Earth into Europe and investigated nature of light, 1250.
Marco Polo lived in China 1275-1295.
Kubla Khan founded observatory in Pekin.
Ibn Batuta explored Asia and Africa.
Probable rise of Inca and Aztec cultures.
William of Wykeham founded Winchester College, 1393.
Prince Henry the Navigator promoted exploration, 1440.
Columbus set sail for India; Martin Behaim made a terrestrial globe, 1492.
"Pythagoreans" worked secretly in Rome.
First agitation for reform which resulted in the Gregorian calendar, 1535.
Apian published Caesars' Astronomy, 1540.
Explorations of the New World.
Copernicus published De Revolutionibus Orbium Coelestium, 1543. (The ghost of Aristarchus laughed.)
Cornerstone laid for Tycho Brahe's Observatory at Uranienburg, 1576.
1609 Galileo first used his telescope; Kepler concluded his "Martian Labour."
1666 Newton was hit on the head by an apple; Royal Society founded.
1675 Greenwich Observatory founded.
1682 Halley computed return of the comet which bears his name.
1781 Herschel discovered Uranus.
1796 Laplace enunciated his nebular hypothesis.
1801 First asteroid, Ceres, discovered.
1802 Dark lines of spectrum discovered by Wollaston, subsequently charted by Fraunhofer.
1840 First photograph (daguerreotype) taken of the Moon.
1845 Earl of Rosse installed 6-foot reflecting telescope.
1846 Calculations of Couche Adams in Cambridge and of Le Verrier in Paris made possible Professor Galle's discovery of Neptune.
1859 Kirchoff applied spectrum-analysis to astrophysics.
1900 Chamberlin and Moulton announced planetisimal theory.
1905 Einstein first enunciated relativity theory.
1919 100-inch telescope installed at Mt. Wilson.
1919 Discovery of Galaxies outside the Milky Way.
1921 Theory of expanding universe expounded.
1930 Pluto discovered.
1957 Launch of Sputnik 1 spacecraft.
1969 Man's Moon landing.