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Mile Rocks Light
Mile Rocks Lighthouse is located on a rock about southwest of the Golden Gate Bridge, off of Lands End in San Francisco, California. It was completed in 1906, replacing a nearby bell buoy. In 1966, the light was automated, and the original tower of the lighthouse was demolished and replaced by a helipad. The lighthouse was at one time painted with alternating red and white rings, but , the lighthouse is painted plain white. History In 1889, the United States Lighthouse Service placed a bell buoy near the rocks. However, strong currents in the area would pull the buoy beneath the surface of the water and set it adrift. On February 22, 1901, the SS ''City of Rio de Janeiro'' wrecked on the rocks, which prompted the lighthouse to be built. One hundred and twenty-eight persons, of 209 aboard, lost their lives when the ship sank. The lighthouse was constructed by contractor James McMahon who hired sailors from San Francisco after his original crew refused to work in the dange ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lands End (San Francisco)
Lands End is a park in San Francisco within the Golden Gate National Recreation Area. It is a rocky and windswept shoreline at the mouth of the Golden Gate, situated between the Sutro District and Lincoln Park and abutting Fort Miley Military Reservation. A memorial to USS ''San Francisco'' stands in the park. Numerous hiking trails follow the former railbeds of the Ferries and Cliff House Railway along the cliffs and also down to the shore. The most-traveled trail in Lands End is the Coastal Trail, a section of the California Coastal Trail that follows the railbed of the old Cliff House Railway. This trail is handicap-accessible until the Mile Rock Overlook, and bike accessible until the Eagles Point steps. A spur trail takes users to Mile Rock Point and Mile Rock Beach, which offer views of the Golden Gate. Additionally, Lands End contains the ruins of the Sutro Baths. Other historic sites include numerous shipwrecks, which are visible at low tides from the Coastal T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouses Completed In 1906
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 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Lighthouses In The United States
This is a list of lighthouses in the United States. The United States has had approximately a thousand lights as well as light towers, range lights, and pier head lights. Michigan has the most lights of any state with over 150 past and present lights. Lighthouses that are in former U.S. territories are not listed here. Most of the lights in the United States have been built and maintained by the Coast Guard (since 1939) and its predecessors, the United States Lighthouse Service (1910–1939) and the United States Lighthouse Board (1852–1910). Before the Lighthouse Board was established, local collectors of customs were responsible for lighthouses under Stephen Pleasonton. As their importance to navigation has declined and as public interest in them has increased, the Coast Guard has been handing over ownership and in some cases responsibility for running them to other parties, the chief of them being the National Park Service under the National Historic Lighthouse Preservatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Diego
San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United States and the seat of San Diego County, the fifth most populous county in the United States, with 3,338,330 estimated residents as of 2019. The city is known for its mild year-round climate, natural deep-water harbor, extensive beaches and parks, long association with the United States Navy, and recent emergence as a healthcare and biotechnology development center. San Diego is the second largest city in the state of California, after Los Angeles. Historically home to the Kumeyaay people, San Diego is frequently referred to as the "Birthplace of California", as it was the first site visited and settled by Europeans on what is now the U.S. west coast. Upon landing in San Diego Bay in 1542, Juan Rodríguez Cabrillo claimed the area for S ... [...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] |
Lighthouse Keeper
A lighthouse keeper or lightkeeper is a person responsible for tending and caring for a lighthouse, particularly the light and lens in the days when oil lamps and clockwork mechanisms were used. Lighthouse keepers were sometimes referred to as "wickies" because of their job trimming the wicks. Duties and functions Historically, lighthouse keepers were needed to trim the wicks, replenish fuel, wind clockworks and perform maintenance tasks such as cleaning lenses and windows. They were also responsible for the fog signal and the weather station, and played a major role in search and rescue at sea. Because most lighthouses are located in remote, isolated or inaccessible areas on islands and coastlines, it was typical for the work of lighthouse keeper to remain within a family, passing from parents to child, all of whom lived in or near the lighthouse itself. "Stag light" was an unofficial term given to some isolated lighthouses in the United States Lighthouse Service. It meant sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Lighthouse Service
The United States Lighthouse Service, also known as the Bureau of Lighthouses, was the agency of the United States Government and the general lighthouse authority for the United States from the time of its creation in 1910 as the successor of the United States Lighthouse Board until 1939 when it was merged into the United States Coast Guard. It was responsible for the upkeep and maintenance of all lighthouses and lightvessels in the United States. History 1789–1910 In 1789, the United States Lighthouse Establishment (USLHE) was created and operated under the Department of the Treasury. All U.S. lighthouse ownership was transferred to the government which became the general lighthouse authority (GLA). In 1792, the Cape Henry Lighthouse was the first lighthouse built by the USLHE. In 1822, French physicist, Augustin Fresnel designed the Fresnel lens. In 1841 the Fresnel lens was first used in the United States and installed on the Navesink Lighthouse. In 1852 the Lighthou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Francisco
San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th most populous in the United States, with 815,201 residents as of 2021. It covers a land area of , at the end of the San Francisco Peninsula, making it the second most densely populated large U.S. city after New York City, and the fifth most densely populated U.S. county, behind only four of the five New York City boroughs. Among the 91 U.S. cities proper with over 250,000 residents, San Francisco was ranked first by per capita income (at $160,749) and sixth by aggregate income as of 2021. Colloquial nicknames for San Francisco include ''SF'', ''San Fran'', ''The '', ''Frisco'', and ''Baghdad by the Bay''. San Francisco and the surrounding San Francisco Bay Area are a global center of economic activity and the arts and sciences, spurre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helipad
A helipad is a landing area or platform for helicopters and powered lift aircraft. While helicopters and powered lift aircraft are able to operate on a variety of relatively flat surfaces, a fabricated helipad provides a clearly marked hard surface away from obstacles where such aircraft can land safely. Larger helipads, intended for use by helicopters and other vertical take-off and landing aircraft (VTOL), may be called ''vertiports.'' An example is Vertiport Chicago, which opened in 2015. Usage Helipads may be located at a heliport or airport where fuel, air traffic control and service facilities for aircraft are available. Most helipads are located remote from populated areas due to sounds, winds, space and cost constraints. However, some skyscrapers maintain a helipad on their roofs in order to accommodate air taxi services. Some basic helipads are built on top of highrise buildings for evacuation in case of a major fire outbreak. Major police departments may use a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouse
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 reef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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