Astronomy Timeline

This is a timeline of important events in astronomical history. Some events which are not specifically astronomical in nature are listed to give historical perspective as to what was happening in those times.

Date                            Location                      Event

c. 3,200 B.C.                   Ireland                        Newgrange is built.

c. 3,000 B.C.                   England                       Stonehenge is built.

c. 2,000 B.C.               Egypt and                   First solar-lunar calendars

                                    Mesopotamia

c. 280 B.C.                  Samos (Alexandria)   Aristrachus suggests the Earth revolves around the Sun.

                                                                        He provides first estimation of Earth-Sun distance.

c. 240 B.C.                  Cyrene (now Shahhat, Libya)            Eratosthenes measures the circumference

                                                                                                of the earth with surprising accuracy!

c. 130 B.C.                  Greece                                    Hipparchus develops the first acccurate star map and

                                                                        star catalogue with over 850 of the brightest stars.

45 B.C.                        Roman Empire           Introduction of the Julian calendar, a purely solar calendar,

                                                                        to the Roman Empire.

140 A.D.                     Greece                                    Ptolemy suggests geocentric theory of the universe

                                                                        in famous work Mathematike Syntaxis.

 813 A.D.                    Iraq                             Al Mamon founds the Baghdad school of astronomy.

1054 A.D.                   China                          Chinese astronomers observe supernova in Taurus.

1543 A.D.                   Poland             Copernicus publishes his heliocentric theory of the Universe.

1572 A.D.                   Denmark                    Tycho Brahe discovers a supernova

                                                                        in constellation of Cassiopeia.

1582 A.D.                   Italy                            Pope Gregory XIII introduces the Gregorian calendar.

1603 A.D.                   Germany                     Johann Bayer introduces Bayer designation of stars,

                                                                        assigning Greek letters to stars, still in use today.

1608 A.D.                   Netherlands                Hans Lippershey, a Dutch spectacles maker

                                                                        invents the telescope.

1609 A.D.                   Italy                            Galileo uses telescope for astronomical purposes.

                                                                        He discovers 4 Jovian moons, the Moon's craters

                                                                        and the Milky Way galaxy.

1609 A.D.                   Germany                     Kepler's First and Second Laws of Planetary Motions

                                                                        are announced.

1609 A.D.                   Germany                     The Third Law of Planetary Motion is announced by Kepler

                                                                        work Harmonice Mudi (Harmony of the World).

1656 A.D.                   Netherlands                Christian Huygens discovers Saturn's rings and Titan,

                                                                        urth satellite of Saturn.

1659 A.D.                   Netherlands                Huygens notes markings on Mars.

1666 A.D.                   Italy                            Martian polar ice caps are noted by Cassini.

1668 A.D.                   England                       The first reflecting telescope was built by Newton.

1669 A.D.                   Italy                            Geminiano Montanari discovers the star Algol is not steady

                                                                        in brightness, thus recognizing the first variable star.

1675 A.D.                   France                         While in Paris, Danish astronomer Ole Romer

                                                                        measures the speed of light.

1675 A.D.                   France                         Cassini discovers that Saturn's rings are split into two parts,

                                                                        so that today the gap is called the "Cassini Division".

1687 A.D.                   England                       Newton publishes his theory of universal gravitation

                                                                        in the work Philosophiae Naturalis Principia Mathematica.                                                                                   This is seen to be the start of Modern Astronomy.

1705 A.D.                   England                       Halley correctly predicts the return of a comet (Halley's comet)

                                                                         in 1758.

1758 A.D.                   Germany                     Johann Palitzsch observes Halley's comet

                                                                        as predicted by Halley in 1705.

1781 A.D.                   England                       Discovery of Uranus by Herschel

1781 A.D.                   France                         Messier discovers galaxies, nebula and star clusters

                                                                        while looking comets.

                                                                        He compiles a catalogue of these objects (Messier objects).

1801 A.D.                   Italy                            Piazzi discovers first asteroid, Ceres.

1842 A.D.                   Austria                        Discovery of the 'Doppler Effect' by Austrian physicist

                                                                        and mathematician, Christian Doppler.

1843 A.D.                   Germany                     Samuel Heinrich Schwabe describes the sunspot cycle.

1846 A.D.                   Germany                     Johann Galle observes and discovers Neptune.

                                                                        His observations were prompted by mathematical calculations

                                                                        by French astronomer Joseph Leverrier and

                                                                        English astronomer John Couch Adams.

1860-63 A.D.              England                       Beginning of spectral analysis of stars by Sir William Huggins

1868 A.D.                   England                       Jansen and Lockyer observe solar prominences.

1872 A.D.                   U.S.A.                         Henry Draper takes a photograph of the stellar spectrum

                                                                        of Vega. This is the first of its kind.

1877 A.D.                   U.S.A.                         Asaph Hall discovers Phobos and Deimos, the moons of Mars.

1877 A.D.                   Italy                            Shiaparelli observes the canals on Mars.

1878 A.D.                   Jupiter                        The Great Red Spot on Jupiter becomes prominent.