Halogen lamp
What energy powered Great Tower Neuwerk from 2007 to 2014?
Great Tower Neuwerk The Great Tower Neuwerk is the most significant building of the Neuwerk island , belonging to Hamburg . Completed in 1310 , the structure is one of the oldest worldwide that was used as lighthouse ( 1814–2014 ) and still standing . This former beacon , watchtower and lighthouse is also the oldest building in Hamburg and oldest secular building on the German coast . History . The construction of the new werk was started in 1300 . It was completed after ten years in 1310 . The style of a keep matches the common Norman tower type of the time . Contrary to some literature , the tower was built in this form from the beginning . The fire in the 1360s destroyed most of the wooden elements and it had to undergo major reconstruction . The original roof was made of lead , and was replaced by copper in 1474 . This was again replaced in 1558 by a tiled roof and by a new copper roof following that . The copper was then used for military purposes in 1916 reconstructed later . The original purpose was to host troops to defend the ships entering and leaving the Elbe from sea and beach pirates . The tower was also refuge for the farmers on the island during storm surges and survivors of shipwrecks over the centuries . The tower marked the most northern measuring point for the triangulation of the Kingdom of Hannover by Carl Friedrich Gauss in July 1825 . Parts of this triangulation net were depicted on the back of last series of the 10 Deutsche Mark note ( 1989–2001 ) . The tower of Neuwerk is officially Hamburgs oldest building . A church in Sinstorf is actually older , but only part of Hamburg since the Greater Hamburg Act of 1937 . The tower is protected under cultural heritage management since 1924 and the surrounding dwelling hill since 1971 . It is used as viewpoint , guesthouse and restaurant . Lighthouse . Before the tower was turned into a lighthouse in 1814 , the dangerous reef and sandbank of Scharhörn was marked by multiple beacons and bearing aids , most importantly the Scharhörnbake . The most important was the bearing of wooden beacons north-west end of Neuwerk and its tower to find the smaller beacon in the open sea . Todays Nord-Bake still shows the form of a beacon to overshadow an open fire once the ships reached this bearing . The Carta Marina shows a fire beacon on Nuge uirk as early as 1539 , but other sources mention the open coal fire beacon not until 1644 : It was a navigational aid during night time . This required 1000 tons of imported Scottish coal a year starting from 1761 . This coal contained more bitumen and burned much brighter than the usual German hard coal . The tower was only turned into a lighthouse on December 20 , 1814 . The first lamp was made of 21 hollow wick oil lamps with parabolic reflectors and burned on colza oil and kerosene starting 1870 . A fresnel lens of measuring a focal length of 700 mm was installed 1892 together with a five-wick kerosene lamp , to improve the brightness even further . This lens is still used today . The lamp was again improved in 1908 , to be first electrified in 1942 . Electricity was needed to shut down the light quickly during World War II . The kerosene lamp were kept in place as there was no emergency power supply and upgraded to propane in 1949 . The luminous intensity was stated in 1952 to be 5700 Hefner lamps ( HK ) 13200 seaside , 1000 for the green and 550 for the red light . The reach of the 1000 watt lamp was roughly 30 kilometers . Is could be seen from Heligoland under good conditions . The classic electric lamp was replaced by a Halogen lamp in fall 2007 . On February 10 , 2014 it was replaced by LED . Although belonging to Hamburg , the lighthouse was operated by the Wasser- und Schifffahrtsamt Cuxhaven , which is responsible for the Elbe estuary . As the lighthouse was non-essential for shipping it was decommissioned on January 1 , 2014 and turned over to the Hamburg Port Authority . On February 10 , 2014 it was officially shut down after almost 200 years in operation and continues as a private light under the authority of Hamburg.The original light characteristic Blk . ( 3 ) w . r . gn . 20 s 16–11 sm was switched to a steady white lamp with a reach of barely 3 nautical miles . The original open coal beacon was replaced by the small lighthouse after the great lighthouse started operating and functioned together with him as leading lights . This allowed for safe passage from north-west over the Vogelsandsteert . The forementioned open fire beacon , the great and small lighthouses and todays Nord-Bake all were established on the same bearing . The small lighthouse was torn down in 1909 . Usage . Apart from the floors for the guesthouse for the Hamburg state guests , the tower is home to the warden , a restaurant and their personnel . The former teacher Heinrich Gechter initiated the use as a hostel for schools of Winterhude in 1920 , which switched to the neighboring barn 1924 . The attic was also home the bird warden from the Verein Jordsand for many years . In the 1600s Royal Protestant Imperial Count Palatine Johann Rist resided at Neuwerk .