^			
Year	Event
BC
2300	Chinese astronomers made their
	earliest observations.
2000	Babylonian priests made their
	observational records.
1900	Stonehenge was constructed:
	first phase.
365	The Chinese observed Jupiter's
	satellites with the naked eye.
C3	Aristarchus argued that the
	Sun is the centre of the
	Solar System.

Year	Event
AD	
c.140	Ptolemy's "Almagest" written;
	his Earth-centred universe
	accepted.
903	Star positions measured by
	Al-Sufi.
1054	Supernova is Taurus recorded
	by Chinese astronomers.
1433	Ulugh Beg star catalogue
	compiled.
1543	Nicolaus Copernicus revived
	the ideas of Aristarchus in
	"De Revolutionibus" of a
	Sun-centred system.
1572	Supernova in Cassiopeia
	observed by Tycho Brahe.
1600	Johannes Kepler begins
	analysing planetary
	observations made by Brahe
	and derives his three laws
	of planetary motion
	(1609-18).
1608	Hans Lippershey invented the
	telescope, which was first
	used by Galileo 1609.
1609	First telescopic observations
	made by Galileo and other
	astronomers.
1631	The transit of mercury across
	the Sun is observed by Gassendi,
	as predicted by Kepler.
1632	The world's first official
	observatory was established in
	Leiden in the Netherlands.
1633	Galileo's theories were
	condemned by the Inquisition.
1638	The famous variable star, Mira
	Ceti, is discovered by Holwarda.
1647	One of the first lunar maps is
	drawn by Hevelius.
1668	The first reflecting telescope
	is constructed by Isaac Newton.
1675	The Royal Greenwich Observatory
	was founded in England.
1687	Isaac Newton's "Principia" was
	published, including his 'law
	of universal gravitation'.
1705	Edmond Halley correctly
	predicted that the comet that
	had passed the Earth in 1682
	would return in 1758; the
	comet was later to be known by
	his name.
1725	The first modern star catalogue
	containing 2884 stars is
	published, based on observations
	made by Flamsteed.
1758	Comet Halley makes its predicted
	return.
1761	The first transit of Venus
	across the Sun observed.
1781	William Herschel discovered
	Uranus and recognised stellar
	systems beyond our Galaxy.
1781	Charles Messier publishes his
	catalogue of star clusters and
	nebulae.
1796	Pierre Laplace elaborated his
	theory of the origin of the
	solar system.
1801	Giuseppe Piazzi discovered the
	first asteroid, Ceres.
1814	Joseph Von Fraunhofer first
	studied absorption lines in the
	solar spectrum.
1838	German astronomer Freidrich
	Wilhelm Bessel makes the first
	interstellar distance
	measurement, of 61 Cygni.
1843	The sunspot cycle announced by
	Heinrich Samuel Schwabe.
1846	Neptune was identified by
	Johann Galle, following
	predictions by John Adams and
	Urbain Leverrier.
1859	Gustav Kirchhoff explained dark
	lines in the Sun's spectrum and
	proved that elements in a hot
	body imprint characteristic
	lines in its spectrum.
1887	The earliest photographic star
	charts were produced.
1889	Edward Barnard took the first
	photographs of the Milky Way.
1891	George Ellery Hale invents a
	spectroheliograph for viewing
	the Sun at a single wavelength.
1912	The Cepheid period-luminosity
	law announced by Henrietta
	Leavitt.
1920	Arthur Eddington began the
	study of interstellar matter.
1923	Edwin Hubble proved that the
	galaxies are systems independent
	of the Milky Way, and by 1930
	had confirmed the concept of an
	expanding universe. He also made
	the first good measurement of
	the distance of M31 in
	Andromeda.
1930	The planet Pluto was discovered
	by Clyde Tombaugh.
1931	Karl Jansky founded radio
	astronomy.
1937	The first radio waves from space
	detected by Grote Reber.
1945	Radar contact with the Moon was
	established by Z Bay of Hungary
	and the US Army Signal Corps
	Laboratory.
1948	The 5m/200 in Hale reflector
	telescope was installed at Mount
	Palomar, California, USA.
1957	The first Sputnik satellite
	(USSR) opened the age of space
	observation.
1962	The first X-ray source was
	discovered in Scorpius.
1963	The first quasar was discovered.
	Background radiation pervading
	space discovered.
1967	The first pulsar was discovered
	by Jocelyn Bell and Antony
	Hewish.
1969	The first crewed Moon landing
	was made by US astronauts.
1976	A 6 m/236 in reflector telescope
	was installed at Mount
	Semirodniki, USSR.
1976	Uranus was discovered to have
	rings.
1977	The spacecrafts "Voyager" 1 and
	2 were launched, passing Jupiter
	and Saturn 1979-1981
1978	The spacecraft's "Pioneer Venus"
	1 and 2 reached Venus.
1978	The satellite of Pluto, Charon,
	was discovered by James Christy
	of the US Naval Observatory.
1986	Halley's comet returned.
	"Voyager 2" flew past Uranus
	and discovered six new moons.
1987	Supernova SN1987A flared up,
	becomming the first supernova
	to be visible to the naked eye
	since 1604.
1988	The most distant individual star
	was recorded - a supernova, 5
	billion light years away, in the
	AC118 cluster of galaxies.
1989	"Voyager 2" flew by Neptune and
	discovered eight moons and three
	rings.
1990	Hubble Space Telescope was
	launched into orbit by the US
	space shuttle.
1991	The space probe "Galileo" flew
	past the asteroid Gaspra,
	approaching it to within
	26,000 km / 16,200 mi.
1992	COBE satellite detected ripples
	from the Big Bang that mark the
	first stage in the formation
	of galaxies.