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Roche's Point Lighthouse
Roche's Point Lighthouse is situated at the entrance to Cork Harbour, Ireland. A lighthouse was first established on 4 June 1817 to guide ships into Cork Harbour. The original tower was deemed too small and in 1835 was replaced by the larger present tower which is 49 feet high with a diameter of 12 feet. Light The original light apparatus consisted of ten Argand oil lamps and ten catoptric reflectors. In 1876 the optic was changed to a Second Order Fresnel lens A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships." The design allows the c ..., which is still in use. The lighthouse was converted to electric in 1970. The character of the light was occulting 20s (on for 15 seconds and off for 5 seconds). This was altered on 15 August 1993 to Fl WR 3s (one white and red flash every three seconds). From A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cork Harbour
Cork Harbour () is a natural harbour and river estuary at the mouth of the River Lee in County Cork, Ireland. It is one of several which lay claim to the title of "second largest natural harbour in the world by navigational area" (after Port Jackson, Sydney). Other contenders include Halifax Harbour in Canada, Trincomalee Harbour in Sri Lanka and Poole Harbour in England. The harbour has been a working port and a strategic defensive hub for centuries, and it has been one of Ireland's major employment hubs since the early 1900s. Traditional heavy industries have waned since the late 20th century, with the likes of the closure of Irish Steel in Haulbowline and shipbuilding at Verolme. It still has strategic significance in energy generation, shipping, refining and pharmaceuticals development. Geography The main tributary to the harbour is the River Lee which, after flowing through Cork city, passes through the upper harbour (Lough Mahon) in the northwest before passing to the we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Republic Of Ireland
Ireland ( ga, Éire ), also known as the Republic of Ireland (), is a country in north-western Europe consisting of 26 of the 32 counties of the island of Ireland. The capital and largest city is Dublin, on the eastern side of the island. Around 2.1 million of the country's population of 5.13 million people resides in the Greater Dublin Area. The sovereign state shares its only land border with Northern Ireland, which is part of the United Kingdom. It is otherwise surrounded by the Atlantic Ocean, with the Celtic Sea to the south, St George's Channel to the south-east, and the Irish Sea to the east. It is a unitary, parliamentary republic. The legislature, the , consists of a lower house, ; an upper house, ; and an elected President () who serves as the largely ceremonial head of state, but with some important powers and duties. The head of government is the (Prime Minister, literally 'Chief', a title not used in English), who is elected by the Dáil and appointed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commissioners Of Irish Lights
The Commissioners of Irish Lights ( ga, Coimisinéirí Soilse na hÉireann), often shortened to Irish Lights or CIL, is the body that serves as the general lighthouse authority for Northern Ireland and the Republic of Ireland and their adjacent seas and islands. As the lighthouse authority for the island of Ireland it oversees the coastal lights and navigation marks provided by the local lighthouse authorities, the county councils and port authorities. It is funded by light dues paid by ships calling at ports in the Republic of Ireland, pooled with dues raised similarly in the United Kingdom. This recognizes that a large volume of shipping, typically transatlantic, relies on the lights provided by Irish Lights. History Signal fires to guide shipping have long existed. Hook Head has the oldest nearly continuous light in Ireland, originally a signal fire or beacon tended by the monk Dubhán in the fifth century. Monks continued to maintain the light until the Cromwellian co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulb And Standby Light Inside Fresnel Lens
In botany, a bulb is structurally a short stem with fleshy leaves or leaf basesBell, A.D. 1997. ''Plant form: an illustrated guide to flowering plant morphology''. Oxford University Press, Oxford, U.K. that function as food storage organs during dormancy. (In gardening, plants with other kinds of storage organ are also called "ornamental bulbous plants" or just "bulbs".) Description The bulb's leaf bases, also known as scales, generally do not support leaves, but contain food reserves to enable the plant to survive adverse conditions. At the center of the bulb is a vegetative growing point or an unexpanded flowering shoot. The base is formed by a reduced stem, and plant growth occurs from this basal plate. Roots emerge from the underside of the base, and new stems and leaves from the upper side. Tunicate bulbs have dry, membranous outer scales that protect the continuous lamina of fleshy scales. Species in the genera ''Allium'', ''Hippeastrum'', '' Narcissus'', and ''Tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Great Britain and Ireland), North Channel, the Irish Sea, and St George's Channel. Ireland is the List of islands of the British Isles, second-largest island of the British Isles, the List of European islands by area, third-largest in Europe, and the List of islands by area, twentieth-largest on Earth. Geopolitically, Ireland is divided between the Republic of Ireland (officially Names of the Irish state, named Ireland), which covers five-sixths of the island, and Northern Ireland, which is part of the United Kingdom. As of 2022, the Irish population analysis, population of the entire island is just over 7 million, with 5.1 million living in the Republic of Ireland and 1.9 million in Northern Ireland, ranking it the List of European islan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argand Lamp
The Argand lamp is a type of oil lamp invented in 1780 by Aimé Argand. Its output is 6 to 10 candelas, brighter than that of earlier lamps. Its more complete combustion of the candle wick and oil than in other lamps required much less frequent trimming of the wick. In France, the lamp is called "Quinquet", after Antoine-Arnoult Quinquet, a pharmacist in Paris, who used the idea originated by Argand and popularized it in France. Quinquet sometimes is credited with the addition of the glass chimney to the lamp. Design The Argand lamp had a sleeve-shaped wick mounted so that air can pass both through the center of the wick and also around the outside of the wick before being drawn into a cylindrical chimney which steadies the flame and improves the flow of air. Early models used ground glass which was sometimes tinted around the wick. An Argand lamp used whale oil, seal oil, colza, olive oil or other vegetable oil as fuel which was supplied by a gravity feed from a reservoir mou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catoptrics
Catoptrics (from grc-gre, κατοπτρικός ''katoptrikós'', "specular", from grc-gre, κάτοπτρον ''katoptron'' "mirror") deals with the phenomena of reflected light and image-forming optical systems using mirrors. A catoptric system is also called a ''catopter'' (''catoptre''). Ancient texts ''Catoptrics'' is the title of two texts from ancient Greece: *The Pseudo-Euclidean ''Catoptrics''. This book is attributed to Euclid, although the contents are a mixture of work dating from Euclid's time together with work which dates to the Roman period., accessed 31 January 2013 It has been argued that the book may have been compiled by the 4th century mathematician Theon of Alexandria. The book covers the mathematical theory of mirrors, particularly the images formed by plane and spherical concave mirrors. *Hero's ''Catoptrics''. Written by Hero of Alexandria, this work concerns the practical application of mirrors for visual effects. In the Middle Ages, this work was fal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fresnel Lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships." The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The ''catadioptric'' form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source and add it to the beam of a lighthouse, making the light visible from greater distances. Description The Fresnel lens redu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouses Completed In 1817
A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lenses and to serve as a beacon for navigational aid, for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, rocks, and safe entries to harbors; they also assist in aerial navigation. Once widely used, the number of operational lighthouses has declined due to the expense of maintenance and has become uneconomical since the advent of much cheaper, more sophisticated and effective electronic navigational systems. History Ancient lighthouses Before the development of clearly defined ports, mariners were guided by fires built on hilltops. Since elevating the fire would improve the visibility, placing the fire on a platform became a practice that led to the development of the lighthouse. In antiquity, the lighthouse functioned more as an entrance marker to ports than as a warning signal for reefs a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouses In The Republic Of Ireland
This is a list of lighthouses in Ireland. The Commissioners of Irish Lights are responsible for the majority of marine navigation aids around the island though a small number are maintained by local harbour authorities. The main list identifies those lighthouses in a clockwise direction starting with Crookhaven, Crookhaven lighthouse, County Cork. Maintained by Commissioners of Irish Lights Maintained by other Irish marine authorities A smaller number of active lighthouses are operated by other authorities, primarily the port and harbour companies located around the Geography of Ireland, Irish coast. Inactive Improvements and changes to the aids to navigation around the Irish coast, has meant that there are a number of lighthouses that have been decommissioned. This list includes those where the tower or structure is still in existence. Some of these have been reused, such as Ferris Point which is now a vessel control tower. Clare Island was turned into a guest house ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
