Astronomy is the scientific study of the Universe and the bodies it contains (excluding Earth). Astronomers are the scientists who study astronomy.
|585 BC||First prediction of eclipse of the Sun|
|130 BC||Hipparchus calculates distance and size of Moon|
|AD 1543||Copernicus shows that the Sun is at the centre of the Solar System|
|1609||Johannes Kepler describes laws of planetary motion|
|1610||Galileo Galilei discovers moons of Jupiter|
|1655||Christiaan Huygens discovers Titan, moon of Saturn|
|1668||Isaac Newton builds first reflecting telescope|
|1687||Isaac Newton publishes theories of motions of planets, etc|
|1705||Edmond Halley predicts return of comet|
|1671-84||Giovanni Cassini discovers four moons of Saturn|
|1774||Charles Messier compiles star catalogue|
|1781||William Herschel discovers 7th planet, Uranus|
|1801||First asteroid, Ceres, discovered by Giuseppe Piazzi|
|1846||Johann Galle and Urbain Le Verrier discover 8th planet Neptune|
|1787-89||Herschel finds two moons of Uranus and two of Saturn|
|1839-40||First photographs of the Moon|
|1894||Flagstaff Observatory, Arizona, founded|
|1905||Einstein’s Special Theory of Relativity first proposed|
|1908||Giant and dwarf stars described|
|1923||Galaxies beyond the Milky Way proved|
|1927||Big Bang theory first proposed|
|1930||Pluto, the 9th planet, discovered by Clyde Tombaugh|
|1959||First photographs of the far side of the Moon by Soviet satellite Luna 3|
|1961||First quasars discovered|
|1967||First pulsars identified|
|1971||Black hole first detected , Mariner 9 spacecraft maps Mars|
|1973||Skylab space laboratory launched|
|1976||Rings of Uranus are discovered|
|1977||Voyager deep space probes are launched|
|1978||Space probes Pioneer 1 and 2 reach Venus|
|1980||Voyager 1 expLores Saturn|
|1985-89||Voyager 2 discovers moons of Uranus arid Neptune|
|1994||Comet Shoemaker-Levy observed crashing into Jupiter|
|1995||Galileo probe reaches Jupiter|
|1997||Mars Pathfinder lands , Cassini probe launched to Saturn|
|1998||International Space Station consttuction starts|
|1999||Chandra X-Ray Observatory launched|
|2003||Galileo probe deliberately crash-landed on Jupiter|
|2006||New Horizons space probe launched to Pluto|
Telescopes and observatories
The following are some of the world’s most famous telescopes and observatories.
– Royal Observatory, Greenwich, London Founded by King Charles II in 1675, but atmospheric and light polLution in London reduced its efficiency. In 1884 the Prime or Greenwich Meridian, O, which passes through the Observatory, was adopted as the basis for aLL mapping and measurements. Longitude measurements refer to west or east of the meridian.
– HerscheL’s “Forty-foot” refLector, SLough
A giant telescope built in 1788 with a 1.2m mirror.
– Birr CastLe, Co. OffaLy, Ireland
The Earl of Rosse’s 1,8m reflecting telescope, built in 1845, was used to discover the spiral form of galaxies. It was the world’s largest until the opening of Mount Wilson and it was recently restored and opened to the public.
Yerkes Observatory, Williams Bay, Wisconsin, USA This im telescope is the biggest refracting instrument made up to this time. It was completed in 1897.
– Mount Wilson Observatory, California, USA
The telescope was installed in 1917 with a mirror size of 2.5m. It was the world’s largest until the Hale.
– HaLe TeLescope, PaLomar Observatory, California, USA
The HaLe’s Sm telescope was first used in 1949.
– Jodrell Bank, Cheshire
Britain’s first and once the world’s largest radio telescope, with a 76m dish, began operating in 1957.
– Arecibo Observatory,Puetro Rico
Completed in 1963,This is the world’s most powerful radio telescope.Its uses include searching for pulsars and quasars and the search for aliens.
– Hubble Space Telescope
The HST was launched in 1990 and orbits 600km above Earth’s atmosphere.It can photograph distant objects with Ten times the detail possible with ground-based telescopes.
– Keck 1 and Keck 2 Telescopes,Mauna Kea Observatory,Hawaii,USA
The two Keck Telescopes were opened in 1992-96.They are situated 4000m up a Hawaiian mountain,so above 40 percent of the Earth’s atmosphere.They are the world’s most powerful ground-based instruments with a 10.82m total aperture made up of 36 hexagonal mirrors.
– Hobby-Eberly Telescope,Mc Donald Observatory,Texas,USA
This Telescope is designed to collect light for spectrum analysis rather than for visual exploration.In operation since 1999,it has an overall diameter of 11m,making it one of the largest optical telescopes ever built.
The first teLescopes were made in 1608 by Dutch optician Hans sley. Italian astronomer Galileo built his own soon after and used it to discover Jupiter’s moons. The earliest type of telescope. known as a refracting telescope, produced a slight distortion of images (called aberration). Since about 1670, astronomers have preferred to use reflecting telescopes, which use mirrors that compensate for the distortion.
- John Couch Adams (Britain, 1819—92) studied the Leonid meteor shower and predicted the existence of Neptune, which was discovered in 1846.
- Edward Emerson Barnard (USA, 1857—1923) discovered Barnard’s Star and Amalthea, a moon of Jupiter.
- NicoLaus Copernicus (Poland, 1473—1 543) showed that the Sun was at the centre of the Solar System.
- GaLiLeo GaLiLei (Italy, 1564—1642) was a mathematician who made important discoveries concerning gravity and motion. He built some of the first telescopes used in astronomy and used them to discover many previously unknown space objects.
- George ELlery Hate (USA, 1868—1 938) pioneered the astronomical study of the Sun and founded observatories, one with a major telescope named after him.
- Edmond HaLLey (Britain, 1656—1 742) predicted the orbits of comets, including the one that bears his name.
- William HerscheL (Germany/Britain, 1738—1822) built huge telescopes, compiled catalogues of stars and discovered moons of Saturn and Uranus.
- Edwin Hubble (USA, 1889—1953) made important discoveries about galaxies. The Hubble Space Telescope was named in his honour.
- Christiaan Huygens (Holland, 1629—95) discovered Saturn’s rings and devised the wave theory of light.
- PercivaL LoweLL (USA, 1855—1916) was founder of the Lowell Observatory, Arizona. He predicted that a planet would be found in the region where Pluto was later discovered.
- Isaac Newton (Britain, 1643—1 727) is considered one of the greatest of all astronomers. His theories of gravity and the motions of planets revolutionized the subject.
- Heinrich OLbers (Germany, 1758—1840) discovered asteroids and comets, one of which was named after him.
- Giuseppe Piazza (Italy, 1746—1826) compiled star catalogues and discovered the first asteroid, Ceres, in 1801.
- CharLes Messier (France, 1730—181 7) studied comets and eclipses, but he is best known for his catalogue of stars.