An automatic lamp changer (or lampchanger) is a device used to ensure that a navigational light such as a marine lighthouse or aero beacon stays lit even if a bulb burns out. Numerous types exist. The common design elements are an array of two or more lamps (or bulbs), installed on a mounting which can rotate to various positions. Each position brings a different lamp into the focal point of an optical assembly. Since signal and navigational lights use sophisticated optics to focus the beam, lampchangers are designed to position the new bulb at the focal point with high precision. The device automatically detects when the currently active lamp has ceased to function and moves the next lamp into place.
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses and to serve as a navigational aid for maritime pilots at sea or on inland waterways.
In geometrical optics, a focus, also called an image point, is the point where light rays originating from a point on the object converge. Although the focus is conceptually a point, physically the focus has a spatial extent, called the blur circle. This non-ideal focusing may be caused by aberrations of the imaging optics. In the absence of significant aberrations, the smallest possible blur circle is the Airy disc, which is caused by diffraction from the optical system's aperture. Aberrations tend to get worse as the aperture diameter increases, while the Airy circle is smallest for large apertures.
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.
The automatic lampchanger was invented by Charles Wallace and patented in 1928. [1] This original model held two headlight lamps from a Model T automobile. The United States Lighthouse Service had these in common use by the 1930s, as they moved to convert all navigational lights to electricity.
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.
Lamp changers in current use may have two, four, or six lamps and use either a spring-loaded mechanism or an electric motor to change lamps when required. They are used in aerodrome beacons and marine navigational aids. [2] [3] [4] [5] [6] [7]
An aerodrome beacon or rotating beacon is a beacon installed at an airport or aerodrome to indicate its location to aircraft pilots at night.
A beacon is an intentionally conspicuous device designed to attract attention to a specific location.
Leading lights are a pair of light beacons, used in navigation to indicate a safe passage for vessels entering a shallow or dangerous channel; and may also be used for position fixing. At night, the lights are a form of leading line that can be used for safe navigation. The beacons consist of two lights that are separated in distance and elevation, so that when they are aligned, with one above the other, they provide a bearing. Range lights are often illuminated day and night.
The Canadian Coast Guard is the coast guard of Canada. Formed in 1962, the coast guard is tasked with marine search and rescue, communication, navigation and transportation issues in Canadian waters, such as navigation aids and icebreaking, marine pollution response and providing support for other Canadian government initiatives. The coast guard operates 119 vessels of varying sizes and 22 helicopters, along with a variety of smaller craft. The Canadian Coast Guard is headquartered in Ottawa, Ontario, and is a Special Operating Agency within Fisheries and Oceans Canada.
The Currituck Beach Light is a lighthouse located on the Outer Banks in Corolla, North Carolina. The Currituck Beach Light was added to the National Register of Historic Places on October 15, 1973.
Raffles Lighthouse is a lighthouse located on Pulau Satumu in the Singapore Strait, about 14 kilometres (8.7 mi) south of the main island of Singapore.
Gravelly Shoals Light is an automated lighthouse that is an active aid to navigation on the shallow shoals extending southeast from Point Lookout on the western side of Saginaw Bay. The light is situated about 2.7 miles (4.3 km) offshore and was built to help guide boats through the deeper water between the southeast end of Gravelly Shoals and Charity Island. Architecturally this is considered to be Art Deco style.
A lighthouse keeper 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.
A navigational aid is any sort of marker which aids the traveler in navigation, usually nautical or aviation travel. Common types of such aids include lighthouses, buoys, fog signals, and day beacons.
The historic Grosse Point Light is located in Evanston, Illinois. Following several shipping disasters near Evanston, residents successfully lobbied the federal government for a lighthouse. Construction was completed in 1873. The lighthouse was added to the National Register of Historic Places on September 8, 1976. On 20 January 1999, the lighthouse was designated a National Historic Landmark. It is maintained under the jurisdiction of the Evanston Lighthouse Park District, an independent taxing authority.
The Manistee Pierhead lights are a pair of active aids to navigation located on the north and south pier in the harbor of Manistee, Michigan, "Lake Michigan’s Victorian Port City."
The VRB-25 is a lighthouse optical system designed and built by Vega Industries Ltd. in Porirua, New Zealand. It was originally designed in 1993-95 with the assistance of the United States Coast Guard to meet USCG requirements for a robust mechanism requiring minimum maintenance. It has become the Coast Guard's standard 12 volt rotating beacon. The company's literature says there are more than 400 installations worldwide. More than a quarter of the active lighthouses in Maine have one installed.
An aerobeacon is a light assembly used to create a fixed or flashing signal visible over long distances. It consists of a high intensity electric lamp mounted with a focusing device in a cylindrical housing, which usually is rotated on a vertical axis with an electric motor. The sweep of the narrow beam thus produced gives the flashing effect. Aerobeacons were originally developed for aviation use, most familiarly as aerodrome beacons, but they also saw extensive use in lighthouses. They were far cheaper to manufacture and maintain than classic glass Fresnel lenses, and more rugged; and they could be mounted exposed to the weather. Historic models include the DCB-24, which used a single parabolic reflector; the DCB-224, a double-beamed version of the DCB-24; and the DCB-36, which used a system of plastic Fresnel lenses. Manufacturers included Carlisle & Finch and the Crouse-Hinds Company. They are still in widespread use.
Tideland Signal, sometimes referred to as Tidelands, is a privately held, Houston, Texas based manufacturer of marine navigational aids, with main offices in Lafayette, Louisiana, Vancouver, British Columbia, Canada, Burgess Hill, UK, Dubai, United Arab Emirates and Singapore. It is the manufacturer of the ML-300 lantern, widely used in lighthouses around the world for more than 50 years. In 2016, Tideland was acquired by Xylem, Inc.
Wharton Reef Light is an inactive lighthouse which used to be located on Wharton Reef in Princess Charlotte Bay off the Cape York Peninsula, Queensland, Australia. When it was deactivated in 1990 it was donated to the Townsville Maritime Museum and it is now on display near the museum. It is the only survivor of a series of twenty automatic lighthouses installed in Queensland during the "Golden Age of Australian Lighthouses" from 1913 to the early 1920s.
Peggys Point Lighthouse, also known as Peggys Cove Lighthouse, is an active lighthouse and an iconic Canadian image. Located within Peggy's Cove, Nova Scotia, it is one of the busiest tourist attractions in the province and is a prime attraction on the Lighthouse Trail scenic drive. The lighthouse marks the eastern entrance of St. Margarets Bay and is officially known as the Peggys Point Lighthouse.
The Racine Reef Light was a lighthouse located in Lake Michigan some two miles east of Racine, Wisconsin, marking the edge of its eponymous shallows. It was torn down in 1961 and replaced with a skeleton tower on the same foundation.
The Gannet Rock Lighthouse is a Canadian lighthouse located on a rocky islet 8 miles (13 km) south of Grand Manan in the Bay of Fundy. It was first lit in 1831 and was staffed until 1996. It was solarized in 2002 and remains operational in 2017. It was declared "surplus to requirements" by the Canadian Coast Guard in 2010 and is no longer being maintained.