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  2. Lighthouse - Wikipedia

    en.wikipedia.org/wiki/Lighthouse

    A Fresnel lens can also capture more oblique light from a light source, thus allowing the light from a lighthouse equipped with one to be visible over greater distances. The first Fresnel lens was used in 1823 in the Cordouan lighthouse at the mouth of the Gironde estuary ; its light could be seen from more than 20 miles (32 km) out. [ 18 ]

  3. History of lighthouses - Wikipedia

    en.wikipedia.org/wiki/History_of_lighthouses

    A Fresnel lens can also capture more oblique light from a light source, thus allowing the light from a lighthouse equipped with one to be visible over greater distances. The first Fresnel lens was used in 1823 in the Cordouan Lighthouse at the mouth of the Gironde estuary in France; its light could be seen from more than 20 miles (32 km) out ...

  4. Fresnel lens - Wikipedia

    en.wikipedia.org/wiki/Fresnel_lens

    These lighthouse Fresnel lens systems typically include extra annular prismatic elements, arrayed in faceted domes above and below the central planar Fresnel, in order to catch all light emitted from the light source. The light path through these elements can include an internal reflection, rather than the simple refraction in the planar ...

  5. List of lighthouses in the United States - Wikipedia

    en.wikipedia.org/wiki/List_of_lighthouses_in_the...

    Boston Light, the oldest light station and second oldest lighthouse structure in the US Charleston Light, the last manned lighthouse built on shore 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.

  6. List of tallest lighthouses in the United States - Wikipedia

    en.wikipedia.org/wiki/List_of_tallest...

    The height of existing lighthouses is expressed in two measures: the height of the tower itself, and the distance from the focal plane (that is, the center) of the light source to the water. The latter can be much greater than the former if the light stands on a promontory.

  7. Light characteristic - Wikipedia

    en.wikipedia.org/wiki/Light_characteristic

    A Morse code light is light in which appearances of light of two clearly different durations (dots and dashes) are grouped to represent a character or characters in the Morse Code. For example, "Mo(A)" is a light in which in each period light is shown for a short period (dot) followed by a long period (dash), the Morse Code for "A".

  8. Lighthouse paradox - Wikipedia

    en.wikipedia.org/wiki/Lighthouse_paradox

    Observed distance traveled by light (from left to right) as light source rotates. At a sufficient distance, the speed at which the beam "moves" may exceed the speed of light. The lighthouse paradox is a thought experiment in which the speed of light is apparently exceeded.

  9. Baltimore Harbor Light - Wikipedia

    en.wikipedia.org/wiki/Baltimore_Harbor_Light

    The Baltimore Harbor Light, officially Baltimore Light and historically Baltimore Harbor Lighthouse is a privately owned caisson lighthouse in the Chesapeake Bay in Maryland. [ 2 ] [ 3 ] [ 4 ] First lit in 1908, it sits at the mouth of the Magothy River , marking the channel which leads northwest to the opening of the Patapsco River , which ...