The Dunsink Observatory is an astronomical observatory established in approximately 1785 near the city of Dublin, Ireland. In ancient Greece and other early civilizations, astronomy consisted largely of astrometry, measuring positions of stars and planets in the sky. ... Categories: Stub | Astronomical observatories ... 1785 was a common year starting on Saturday (see link for calendar). ... Dublin (Irish: Baile Átha Cliath1),is the capital and largest city of the Republic of Ireland, located2 near the midpoint of Irelands east coast, at the mouth of the River Liffey and at the centre of the Dublin region3. ...

Its most famous director was William Rowan Hamilton, who, amongst other things, discovered quaternions, the first non-commutative algebra, while strolling from the observatory into the centre of the city with some his wife. He is also renowned for his Hamiltonian formulation of dynamics. In the late 20th century, the city encroached ever more on the observatory, which compromised the seeing. The telescope then, no longer state of the art, was used mainly for public 'open nights'. William Rowan Hamilton Sir William Rowan Hamilton (August 4, 1805 – September 2, 1865) was an Irish mathematician, physicist, and astronomer. ... In mathematics, the quaternions are a non-commutative extension of the complex numbers. ... In mathematics, especially abstract algebra, a binary operation * on a set S is commutative if x * y = y * x for all x and y in S. Otherwise * is noncommutative. ... Algebra is a branch of mathematics which studies structure and quantity. ... In physics, Hamiltonian has distinct but closely related meanings. ... (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901–2000 in the sense of the Gregorian calendar (1900–1999 in the... The word seeing can mean more than one thing: In common usage, the word means visual perception In astronomy, seeing is a technical term related to the clarity of the atmosphere In the occult seeing refers to the sight or the ablity to see auras or to predict the future... 50 cm refracting telescope at Nice Observatory. ...

See also

• Dublin Institute for Advanced Studies

The Dublin Institute for Advanced Studies (Irish: Institiúid Ard-Léinn Bhaile Átha Cliath) at 65 Merrion Square, Dublin, Ireland was established in 1940 by the Taoiseach of the time Eamon de Valera. ...

External Links

• Dunsink Observatory