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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, 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 the 15 August 1993 to Fl WR 3s (one white and red flash every three seconds). From April 1978 the light has been exhibited in conditions of poor visibility while the fog signal was sounding. Roche's Point has red sectors built into the main light to mark navigational hazards approaching the harbour. The sectors are as follows:〔 〕 * Red: shore-292° * White: 292°-016° (84°) * Red: 016°-033° (17°) * White: 033°-159° (126°) * Red: 159°-shore The part of the light that is seen from land is unintensified so as not to disturb those on shore. The light at full intensity (facing sea) has a range of 20 nautical miles for the white light (37.04 km) and 17 nautical miles for the red sector (31.5 km). The light is 30 meters above high water and continues to be exhibited by day in periods of poor visibility. The lighthouse and adjacent buildings are painted white for daytime conspicuousness. The Roche's Point lighthouse was automated in 1995.〔 〕 Apart from the engine house and adjacent building, all the other buildings were sold at public auction. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Roche's Point Lighthouse」の詳細全文を読む スポンサード リンク
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