Snipfact:

    Founded by King Charles II in 1675, but atmospheric and light pollution in London reduced its efficiency. In 1884 the prime or Greenwich Meridian, 0 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.

  Charles Messier (France, 1730-1817) studied comets and eclipses, but he is best known for his catalogue of starts first published in 1774.

    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.

    Edwin Hubble (USA, 1889-1953 made important discoveries about galaxies. The Hubble Space Telescope was named in his honour.

    Christian Huygens (Holland, 1629-95 discovered Saturn’s rings and devised the wave theory of light.

  William Herschel (Germany/Britain, 1738-1822) built huge telescopes, compiled catalogues of stars and discovered moon of Saturn and Uranus.

Edmond Halley (Britain, 1656-1742) predicted the orbits of comets, including the one that bears his name

George Ellery Hale (USA, 1868-1938) pioneered the astronomical study of the Sun and founded observatories, one with a major telescope named after him.

 Galileo Galilei (Italy, 1564-1642) 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.

    Nicolaus Copernicus (Poland, 1473-1543) showed that the Sun was at the centre of the solar System.

     Edward Emerson Barnard (USA, 1857-1923) discovered Barnard's Star and Amathea, a moon of Jupiter.

John Couch Adams (Britain, 1819-92) studied the Leonid meteor shower and predicted the existence of Neptune, which was discovered in 1846.

   The first telescope were made in 1608 by Dutchman Hans Lippershey. Galileo built his own soon after and used it to 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 used reflecting telescopes, which use mirrors that compensate for the distortion.

    British astronomer Edmond Halley (1656 -1742) was the first to prove that comets travel in orbits, making it possible to calculate when they will next be seen from Earth. He predicted that the comet he saw in 1682 would return in 1759. It did and was named in his honour. The regular orbit of Halley’s Comet means that we can find historical accounts f its appearances going back more than 2,000 years. They were often believed to foretell great events. 25may 240 BC Seen in China 10 October 12 BC Believed to mark the death of Roman general Agrippa 28 June AD 451 Believed to mark the defeat of Attila the Hun 20 March 1066 William (later William the Conquer) believed the comet foretold victory over King Harold at the Battle of Hastings. The comet and battle are later depicted in the Bayeux Tapestry. 9 June 1456 The defeat  of the Turkish army by Papal forces was thought to be linked to the comet. 15 September 1682 Observed by Edmond Halley, who predicted its return 13 Mar

        Titan is the largest of Saturn’s 34 moons, It is 5,150 km in diameter –larger than the planet Mercury. Dutch astronomer Christian Huygens discovered Titan in 1655. We still have no idea what its surface looks like because Titan has a dense atmosphere containing nitrogen, ethane and other gases which shroud its surface –not unlike that of Earth four billion years ago.

 Toutatis (asteroid 4,179) was discovered in 1989. It is named after the Celtic god Toutatis, whose name is used as an oath by the comic strip character Asterix the Gaul. Toutatis measures 4.6 by 2.4 by 1.9 km . It passes Earth every four years and is one of the largest space objects to come so close to us. On 29 September 2004 Toutatis came within 1,555,818 km of Earth. Its next visit will be on 9 November 2008, when it will come within 7,524,773 km.

 Astronomers believe that, on average, one asteroid larger than 0.4 km strikes Earth every 50,000 years. Some 65 million years ago a 10 km diameter asteroid crashing to Earth may have been responsible for wiping out the dinosaurs. It would have caused a catastrophic explosion, affecting the climate and chemical composition of the atmosphere and destroying the plants and animals on which the dinosaurs fed. As recently as 1991 a small asteriod came within 170,600 km of Earth, the closest recorded near miss. On 30 Jan 2052 is asteroid is predicted to pass as close as 119,678 km.   

  Ceres was once considered the largest asteroid but it has been recently reclassified as a dwarf planet. It is 936 km in diameter and was found on New Year’s Day, 1801. Since then thousands of asteroids have been found. Twelve   of them are more than 200 km in diameter. As telescopes have improved, more and more small asteroids have been detected . There are probably about 100,000 asterods larger than 1 km in diameter. Some experts think there may be as many as   1.2 million. Vesta, the fourth asteroid to be found   (in 1807), is the only one bright enough to be seen without a telescope.

  Asteroids are often called minor planets. They are lumps of rock orbiting the Sun, mostly in the asteroid belt between the orbits of Mars and Jupiter.

  Titan, discovered in 1846, is the only known large moon in the Solarr system with a retrograde orbit. It revolves around its planet (Neptune) in the opposite direction to the planet’s   rotation.

      More than 20 comets   return more often than Halley.The most frequent visitor is Encke’s comet, named after the German astronomer Johann Franz Encke (1791 -1865 ). In 1818 he calculated   the 3.3 –year period of its orbit.

  The far side of our Moon always faces away from Earth, so it was unknown until October 1959, when the Soviet luna 3 probe sent picture of it back to Earth. 

       Earth’s Moon is the most familiar and also the largest satellite in relation to its planet in the solar system. It is the first body in the Solar System on which vehicles from Earth landed, and the only one to be explored by humans. Earth’s Moon is the most familiar and also the largest satellite in relation to its planet in the solar system. It is the first body in the Solar System on which vehicles from Earth landed, and the only one to be explored by humans. Diameter: 3,475.6 km Distance from Earth: 406,711 km (furthest, 1912) to 356,375 km (closest, 1984), 384,403 km (average) Mass: 734,556,000,000 tonnes; a person weighing 65 kg on Earth would Weigh 10.79 kg on the Moon Rotation: 27 days 7 hours  43 minutes 11.5 seconds Surface temperature: -163 ◦ C to +117 ◦ C Largest crater: South pole Aitken (far side) 2,100 km diameter, 12 km deep (largest in the Solar System)

On 24 August 2006, the International Astronomical Union downgraded Pluto from planetary status. It is now regardeed as belonging to a new “dwarf planet” category, along with Eris, discovered in 2005, and Cares, which used to be regarded as the largest asteroid. The spacecraft New Horizons is scheduled to reach Pluto in 2015.