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VLB-44
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. Components A microprocessor controlled 12 volt DC motor drives an array of six or eight acrylic Fresnel lenses around a bulb at one of 248 speeds ranging from 0.5 to 15.9 revolutions per minute (RPM). In the simplest case, all six lenses are used, so that for Boon Island Light, which shows one flash every five seconds, the mechanism rotates at two RPM. Eight lenses are used only when required to achieve more complex characteristics. Maximum range is achieved by using the slowest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Island Light
The Isles of Shoals Light, also known as "White Island Light", on White and Seavey Islands, White Island, in the Isles of Shoals, New Hampshire, was first built in 1821. The present structure was built in 1865. The lighthouse and the island are protected by the state as White Island State Historic Site. History Captain Samuel Haley began keeping a lantern lit in 1790, but the first lighthouse was not built until 1821, following the 1813 wreck of the ''Sagunte''. Following his defeat for Governor of New Hampshire in 1839, Thomas B. Laighton became keeper of the light. Five years earlier he had purchased Appledore Island, Appledore, Smuttynose Island, Smuttynose, Malaga, and Cedar Islands, on the Maine side of the Isles of Shoals, from Captain Haley. Laighton later built a hotel on Smuttynose. The lighthouse was rebuilt during the American Civil War, Civil War with granite walls two feet thick. It was automated in 1987, but fell into disrepair and was rescued by the efforts of The L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Highland Lighthouse 5
Highlands or uplands are areas of high elevation such as a mountainous region, elevated mountainous plateau or high hills. Generally speaking, upland (or uplands) refers to ranges of hills, typically from up to while highland (or highlands) is usually reserved for ranges of low mountains. However, the two terms are sometimes interchangeable. Highlands internationally Probably the best-known area officially or unofficially referred to as ''highlands'' in the Anglosphere is the Scottish Highlands in northern Scotland, the mountainous region north and west of the Highland Boundary Fault. The Highland council area is a local government area in the Scottish Highlands and Britain's largest local government area. Other highland or upland areas reaching 400-500 m or higher in the United Kingdom include the Southern Uplands in Scotland, the Pennines, North York Moors, Dartmoor and Exmoor in England, and the Cambrian Mountains in Wales. Many countries and regions also have areas refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boon Island Light
Boon Island Light is located on the Boon Island off the southern coast of Maine, United States, near Cape Neddick. Boon Island Light has the distinction of being the tallest lighthouse in both Maine and New England at . The lighthouse has a focal plane at above mean high water. The light's beacon flashes white every 5 seconds. History Talk of building a lighthouse on Boon Island dates back as early as 1710 when the ship ''Nottingham Galley'' ran aground on the barren outcrop that makes up the island. The crew of the ''Galley'' were forced to resort to cannibalism before being rescued. In 1799 the first day marker and a 50-foot wooden tower were established on the island, but it was washed away in the first 5 years. A stone day beacon was established in its place. In 1811 the station was converted to a full light station and a granite tower was constructed. This first tower was washed away in a storm in 1832. The current 133 foot cylindrical brown granite tower was constructed i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Graves Light
The Graves Light is a lighthouse located on The Graves (Massachusetts), The Graves, the outermost island of the Boston Harbor Islands National Recreation Area, and offshore of downtown Boston, Massachusetts, Boston, Massachusetts, USA. At , it is the tallest lighthouse in the approaches to the Port of Boston, and is an important navigation aid for traffic to and from the port. It was built at the same time that the North Channel into Boston Harbor was dredged to become the principal entrance for large vessels. The Graves are the outermost rocks near the outer end of the North Channel. It was added to the National Register of Historic Places as Graves Light Station on September 28, 1987, reference number 87002041. Construction and history The lighthouse was built in 1905, to a conical design using granite blocks on a granite foundation, and equipped with one of the few first-order Fresnel lens used. The lens assembly stands about 12 ft (4m) tall and is now at the Smithsonia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg Rock Light (Maine)
Egg Rock Light is a lighthouse on Frenchman Bay, Maine. Built in 1875, it is one of coastal Maine's architecturally unique lighthouses, with a square tower projecting through the square keeper's house. Located on Egg Rock, midway between Mount Desert Island and the Schoodic Peninsula, it is an active aid to navigation, flashing red every 40 seconds. The light was listed on the National Register of Historic Places as Egg Rock Light Station in 1988. Description and history The Egg Rock Light Station consists of two buildings, a combination light tower and keeper's house, and a fog station building. The keeper's house is a roughly square -story wood-frame building, with a hip roof pierced by dormers on all four sides. The painted brick tower, high, rises through the center of the house. The light is a VRB-25 aerobeacon, mounted in a 1986 replacement lantern house. It is configured to flash red every 40 seconds. The fog station is a brick structure southwest of the main buildin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionization, ionize atoms, it can cause chemical reactions and causes many substances to glow or fluorescence, fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse-width Modulation
Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a method of reducing the average power delivered by an electrical signal, by effectively chopping it up into discrete parts. The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast rate. The longer the switch is on compared to the off periods, the higher the total power supplied to the load. Along with maximum power point tracking (MPPT), it is one of the primary methods of reducing the output of solar panels to that which can be utilized by a battery. PWM is particularly suited for running inertial loads such as motors, which are not as easily affected by this discrete switching, because their inertia causes them to react slowly. The PWM switching frequency has to be high enough not to affect the load, which is to say that the resultant waveform perceived by the load must be as smooth as possible. The rate (or frequency) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incandescent Light Bulb
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxidation. Current is supplied to the filament by terminals or wires embedded in the glass. A bulb socket provides mechanical support and electrical connections. Incandescent bulbs are manufactured in a wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, and work equally well on either alternating current or direct current. As a result, the incandescent bulb became widely used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, and flashlights, and for decorative and advertising lighting. Incandescent bulbs are much less efficient than other types of electric lighting, converting les ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Cuckolds Light
The Cuckolds Light, known as the Cuckolds Island Fog Signal and Light Station or just Cuckolds Light Station, is a lighthouse located on the eastern pair of islets known as the "Cuckolds" in Lincoln County, Maine. The islets are southeast and in sight of Cape Island, that is just off the southern tip of Cape Newagen on Southport Island, south of Booth Bay, that leads to Boothbay Harbor, Maine. The fog station was first established as a daymark on November 16, 1892, for marking the islets and Collector ledge replacing a 57-foot-tall wooden tripod, In 1893 a bell was installed and a light was added in 1907. The keepers house was demolished following the 1974 decommission but was rebuilt from 2010 to 2014, along with the wharf, and the lighthouse restored. The Cuckolds Light was added to the National Register of Historic Places listings in Lincoln County, Maine as Cuckolds Light Station on December 2, 2002. History The United States Congress appropriated funding through the Lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Characteristic
A light characteristic is all of the properties that make a particular navigational light identifiable. Graphical and textual descriptions of navigational light sequences and colours are displayed on nautical charts and in Light Lists with the chart symbol for a lighthouse, lightvessel, buoy or sea mark with a light on it. Different lights use different colours, frequencies and light patterns, so mariners can identify which light they are seeing. Abbreviations While light characteristics can be described in prose, e.g. "Flashing white every three seconds", lists of lights and navigation chart annotations use abbreviations. The abbreviation notation is slightly different from one light list to another, with dots added or removed, but it usually follows a pattern similar to the following (see the chart to the right for examples). * An abbreviation of the type of light, e.g. "Fl." for flashing, "F." for fixed. * The color of the light, e.g. "W" for white, "G" for green, "R" for red, ... [...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] |
