Misplaced Pages

#130869

126-624: The New Dungeness Lighthouse is a functioning aid to navigation on the Strait of Juan de Fuca , located on the Dungeness Spit in the Dungeness National Wildlife Refuge near Sequim , Clallam County , in the U.S. state of Washington . It has been in continuous operation since 1857, although the current lighthouse tower is 26 feet (7.9 m) shorter than when first constructed. The New Dungeness Light

252-607: A guild of navigators who had very high status; in times of famine or difficulty, they could trade for aid or evacuate people to neighbouring islands. As of 2014, these traditional navigation methods are still taught in the Polynesian outlier of Taumako in the Solomons and by voyaging societies throughout the Pacific. Both wayfinding techniques and outrigger canoe construction methods have been kept as guild secrets , but in

378-421: A nautical almanac , can be used to calculate the time at zero longitude (see Greenwich Mean Time ). Reliable marine chronometers were unavailable until the late 18th century and not affordable until the 19th century. For about a hundred years, from about 1767 until about 1850, mariners lacking a chronometer used the method of lunar distances to determine Greenwich time to find their longitude. A mariner with

504-433: A sextant and using sight reduction tables to correct for height of eye and atmospheric refraction. The height of Polaris in degrees above the horizon is the latitude of the observer, within a degree or so. Similar to latitude, the longitude of a place on Earth is the angular distance east or west of the prime meridian or Greenwich meridian . Longitude is usually expressed in degrees (marked with °) ranging from 0° at

630-611: A Polynesian catamaran found in Auckland Museum . The boats were built in the Philippines by an experienced boat builder to Wharram's designs using modern strip plank with epoxy resin glue built over plywood frames. The catamarans had modern Dacron sails, Terylene stays and sheets with modern roller blocks. Wharram says he used Polynesian navigation to sail along the coast of Northern New Guinea and then sailed 150 miles to an island for which he had modern charts, proving that it

756-512: A Polynesian pre-Columbian origin, a later report looking at the same specimens concluded: A published, apparently pre-Columbian, Chilean specimen and six pre-European Polynesian specimens also cluster with the same European/Indian subcontinental/Southeast Asian sequences, providing no support for a Polynesian introduction of chickens to South America. In contrast, sequences from two archaeological sites on Easter Island group with an uncommon haplogroup from Indonesia, Japan, and China and may represent

882-726: A Portuguese expedition commanded by Vasco da Gama reached India by sailing around Africa, opening up direct trade with Asia . Soon, the Portuguese sailed further eastward, to the Spice Islands in 1512, landing in China one year later. The first circumnavigation of the earth was completed in 1522 with the Magellan-Elcano expedition , a Spanish voyage of discovery led by Portuguese explorer Ferdinand Magellan and completed by Spanish navigator Juan Sebastián Elcano after

1008-525: A castaway group of Tahitians who had become lost at sea in a gale and blown 1000 miles away to the island of Atiu . Cook wrote that this incident "will serve to explain, better than the thousand conjectures of speculative reasoners, how the detached parts of the earth, and, in particular, how the South Seas, may have been peopled". By the late 19th century to the early 20th century, a more generous view of Polynesian navigation had come into favor, creating

1134-691: A chronometer could check its reading using a lunar determination of Greenwich time. In navigation, a rhumb line (or loxodrome) is a line crossing all meridians of longitude at the same angle, i.e. a path derived from a defined initial bearing. That is, upon taking an initial bearing, one proceeds along the same bearing, without changing the direction as measured relative to true or magnetic north. Most modern navigation relies primarily on positions determined electronically by receivers collecting information from satellites. Most other modern techniques rely on finding intersecting lines of position or LOP. A line of position can refer to two different things, either

1260-595: A description of icebergs surrounded by sea ice found in the Southern Ocean . The account also describes snow. In the mid-20th century, Thor Heyerdahl proposed a new theory of Polynesian origins (one which did not win general acceptance), arguing that the Polynesians had migrated from South America on balsa -log boats. The presence in the Cook Islands of sweet potatoes , a plant native to

1386-478: A distance produces a circle or arc of position. Circles, arcs, and hyperbolae of positions are often referred to as lines of position. If the navigator draws two lines of position, and they intersect he must be at that position. A fix is the intersection of two or more LOPs. If only one line of position is available, this may be evaluated against the dead reckoning position to establish an estimated position. Lines (or circles) of position can be derived from

SECTION 10

#1732800983131

1512-410: A faint green colour on to the clouds above the atoll. If the navigator drifted off their course, they could correct their course when they sighted the reflection of the lagoon in the clouds in the distance. Dr. David Lewis was one of the first academics, along with Marianne George, to document an unexplained light phenomenon. Te lapa is a burst of light in a straight line occurring on, or just below

1638-612: A few meters using time signals transmitted along a line of sight by radio from satellites . Receivers on the ground with a fixed position can also be used to calculate the precise time as a reference for scientific experiments. As of October 2011, only the United States NAVSTAR Global Positioning System (GPS) and the Russian GLONASS are fully globally operational GNSSs. The European Union 's Galileo positioning system

1764-467: A genetic signature of an early Polynesian dispersal. Modeling of the potential marine carbon contribution to the Chilean archaeological specimen casts further doubt on claims for pre-Columbian chickens, and definitive proof will require further analyses of ancient DNA sequences and radiocarbon and stable isotope data from archaeological excavations within both Chile and Polynesia. However, in a later study,

1890-495: A group of islands would learn the effect various islands had on the swell shape, direction, and motion, and would have been able to correct their path accordingly. Even when they arrived in the vicinity of an unfamiliar chain of islands, they may have been able to detect signs similar to those of their home. Once they had arrived fairly close to a destination island, they would have been able to pinpoint its location by sightings of land-based birds, certain cloud formations, as well as

2016-490: A large body of knowledge from oral tradition . This island hopping was a solution to the scarcity of useful resources, such as food, wood, water, and available land, on the small islands in the Pacific Ocean. When an island’s required resources for human survival began to run low, the island's inhabitants used their maritime navigation skills and set sail for new islands. However, as an increasing number of islands in

2142-402: A line on a chart or a line between the observer and an object in real life. A bearing is a measure of the direction to an object. If the navigator measures the direction in real life, the angle can then be drawn on a nautical chart and the navigator will be somewhere on that bearing line on the chart. In addition to bearings, navigators also often measure distances to objects. On the chart,

2268-407: A much more reliable method of navigation than waves, which are determined by the local winds. Swells move in a straight direction which makes it easier for the navigator to determine whether the canoe is heading in the correct direction. Polynesian navigators could identify the clouds that resulted from the white sand of coral atolls reflecting heat into the sky. Subtle differences in the colour of

2394-432: A much romanticized view of their seamanship, canoes, and navigational expertise. Late 19th- and early 20th-century writers such as Abraham Fornander and Percy Smith told of heroic Polynesians migrating in great coordinated fleets from Asia far and wide into present-day Polynesia. Another view was presented by Andrew Sharp, who challenged the "heroic vision" hypothesis, asserting instead that Polynesian maritime expertise

2520-602: A navigator. However, in February 1778, Cook recorded his impressions of the dispersal and settlement of Polynesian people across the Pacific ocean in favorable terms: How shall we account for this nation's having spread itself, in so many detached islands, so widely disjoined from each other in every quarter of the Pacific Ocean? We find it, from New Zealand, in the South, as far as the Sandwich Islands (Hawaiʻi), to

2646-450: A number of stars in succession to give a series of overlapping lines of position. Where they intersect is the celestial fix. The Moon and Sun may also be used. The Sun can also be used by itself to shoot a succession of lines of position (best done around local noon) to determine a position. In order to accurately measure longitude, the precise time of a sextant sighting (down to the second, if possible) must be recorded. Each second of error

SECTION 20

#1732800983131

2772-399: A particularly good navigation system for ships and aircraft that might be flying at a distance from land. RDFs works by rotating a directional antenna and listening for the direction in which the signal from a known station comes through most strongly. This sort of system was widely used in the 1930s and 1940s. RDF antennas are easy to spot on German World War II aircraft, as loops under

2898-418: A radio time signal. Times and frequencies of radio time signals are listed in publications such as Radio Navigational Aids . The second critical component of celestial navigation is to measure the angle formed at the observer's eye between the celestial body and the sensible horizon. The sextant, an optical instrument, is used to perform this function. The sextant consists of two primary assemblies. The frame

3024-400: A single object," "two or more bearings," "tangent bearings," and "two or more ranges." Radar can also be used with ECDIS as a means of position fixing with the radar image or distance/bearing overlaid onto an Electronic nautical chart . Parallel indexing is a technique defined by William Burger in the 1957 book The Radar Observer's Handbook . This technique involves creating a line on

3150-579: A stalemate between the romantic and the skeptical views. Anthropologist David Lewis sailed his catamaran from Tahiti to New Zealand, via Rarotonga using stellar navigation without instruments. David Lewis also sought out navigators of the Caroline Islands , Santa Cruz Islands and Tonga to confirm that traditional navigation techniques had been retained by navigators from Polynesia, Micronesia and Melanesia. The voyages of David Lewis on his ketch Isbjorn included: Tevake navigating between

3276-404: A sufficient depth of water below the hull as well as a consideration for squat . It may also involve navigating a ship within a river, canal or channel in close proximity to land. A military navigation team will nearly always consist of several people. A military navigator might have bearing takers stationed at the gyro repeaters on the bridge wings for taking simultaneous bearings, while

3402-400: A survival guide he wrote for the U.S. military during World War II, Gatty outlined various Polynesian navigation techniques for shipwrecked sailors or aviators to find land. There are some references in their oral traditions to the flight of birds, and Gatty claimed that departing voyages used onshore range marks pointing to distant islands in line with their flight paths. A voyage from Tahiti,

3528-413: A variety of sources: There are some methods seldom used today such as "dipping a light" to calculate the geographic range from observer to lighthouse. Methods of navigation have changed through history. Each new method has enhanced the mariner's ability to complete his voyage. One of the most important judgments the navigator must make is the best method to use. Some types of navigation are depicted in

3654-453: Is Pulsar navigation , which compares the X-ray bursts from a collection of known pulsars in order to determine the position of a spacecraft. This method has been tested by multiple space agencies, such as NASA and ESA . A radio direction finder or RDF is a device for finding the direction to a radio source. Due to radio's ability to travel very long distances "over the horizon", it makes

3780-449: Is a next generation GNSS in the final deployment phase, and became operational in 2016. China has indicated it may expand its regional Beidou navigation system into a global system. Polynesian navigation Polynesian navigation or Polynesian wayfinding was used for thousands of years to enable long voyages across thousands of kilometres of the open Pacific Ocean . Polynesians made contact with nearly every island within

3906-436: Is a quartz crystal oscillator. The quartz crystal is temperature compensated and is hermetically sealed in an evacuated envelope. A calibrated adjustment capability is provided to adjust for the aging of the crystal. The chronometer is designed to operate for a minimum of one year on a single set of batteries. Observations may be timed and ship's clocks set with a comparing watch, which is set to chronometer time and taken to

New Dungeness Light - Misplaced Pages Continue

4032-425: Is a rigid triangular structure with a pivot at the top and a graduated segment of a circle, referred to as the "arc", at the bottom. The second component is the index arm, which is attached to the pivot at the top of the frame. At the bottom is an endless vernier which clamps into teeth on the bottom of the "arc". The optical system consists of two mirrors and, generally, a low power telescope. One mirror, referred to as

4158-1053: Is considered to be the V-2 guidance system deployed by the Germans in 1942. However, inertial sensors are traced to the early 19th century. The advantages INSs led their use in aircraft, missiles, surface ships and submarines. For example, the U.S. Navy developed the Ships Inertial Navigation System (SINS) during the Polaris missile program to ensure a reliable and accurate navigation system to initial its missile guidance systems. Inertial navigation systems were in wide use until satellite navigation systems (GPS) became available. INSs are still in common use on submarines (since GPS reception or other fix sources are not possible while submerged) and long-range missiles. Not to be confused with satellite navigation, which depends upon satellites to function, space navigation refers to

4284-441: Is equivalent to 15 seconds of longitude error, which at the equator is a position error of .25 of a nautical mile, about the accuracy limit of manual celestial navigation. The spring-driven marine chronometer is a precision timepiece used aboard ship to provide accurate time for celestial observations. A chronometer differs from a spring-driven watch principally in that it contains a variable lever device to maintain even pressure on

4410-623: Is helpful to the technique of marking directions with the rising and setting points of identified stars. On his first voyage of Pacific exploration , Captain James Cook had the services of a Polynesian navigator, Tupaia , who drew a chart of the islands within a 2,000 miles (3,200 km) radius (to the north and west) of his home island of Ra'iatea . Tupaia had knowledge of 130 islands and named 74 on his chart. Tupaia had navigated from Ra'iatea in short voyages to 13 islands. He had not visited western Polynesia, as since his grandfather's time

4536-478: Is not affected by adverse weather conditions and it cannot be detected or jammed. Its disadvantage is that since the current position is calculated solely from previous positions and motion sensors, its errors are cumulative, increasing at a rate roughly proportional to the time since the initial position was input. Inertial navigation systems must therefore be frequently corrected with a location 'fix' from some other type of navigation system. The first inertial system

4662-453: Is particularly useful due to their high power and location near major cities. Decca , OMEGA , and LORAN-C are three similar hyperbolic navigation systems. Decca was a hyperbolic low frequency radio navigation system (also known as multilateration ) that was first deployed during World War II when the Allied forces needed a system which could be used to achieve accurate landings. As

4788-479: Is possible, sailing with the Roaring Forties . In 1834, some escapees from Tasmania arrived at Chiloe Island after sailing for 43 days. A Mangarevan legend tells of Anua Matua who sailed in south-west direction reaching southernmost South America. Knowledge of the traditional Polynesian methods of navigation was widely lost after contact with and colonization by Europeans. This caused debates over

4914-497: Is probably the earliest form of open-ocean navigation; it was based on memory and observation recorded on scientific instruments like the Marshall Islands Stick Charts of Ocean Swells . Early Pacific Polynesians used the motion of stars, weather, the position of certain wildlife species, or the size of waves to find the path from one island to another. Maritime navigation using scientific instruments such as

5040-480: Is radiocarbon dating evidence of visits from Polynesians by 1500. The material evidence of Polynesian visits to at least one of the subantarctic islands to the south of New Zealand consists of the remains of a settlement. This evidence from Enderby Island in the Auckland Islands has been radiocarbon dated back to the 13th Century. Absence of remains further south than Enderby Island may imply there

5166-459: Is reasonable for the navigator to simply monitor the progress of the ship along the chosen track, visually ensuring that the ship is proceeding as desired, checking the compass, sounder and other indicators only occasionally. If a pilot is aboard, as is often the case in the most restricted of waters, his judgement can generally be relied upon, further easing the workload. But should the ECDIS fail,

New Dungeness Light - Misplaced Pages Continue

5292-431: Is that voyagers took a frigatebird ( Fregata ) with them. This bird's feathers become drenched and useless if it lands on water, so voyagers would release it when they thought they were close to land, and would follow it if it did not return to the canoe. The positions of the stars helped guide Polynesian voyages. Stars, as opposed to planets, hold fixed celestial positions year-round, changing only their rising time with

5418-705: Is unrelated. If it occurred, this contact left no genetic legacy in California or Hawaii. This theory has attracted limited media attention within California, but most archaeologists of the Tongva and Chumash cultures reject it on the grounds that the independent development of the sewn-plank canoe over several centuries is well-represented in the material record. Polynesian contact with the prehispanic Mapuche culture in central-south Chile has been suggested because of apparently similar cultural traits, including words like toki (stone axes and adzes), hand clubs similar to

5544-564: The Age of Discovery . The earliest known description of how to make and use a sea astrolabe comes from Spanish cosmographer Martín Cortés de Albacar 's Arte de Navegar ( The Art of Navigation ) published in 1551, based on the principle of the archipendulum used in constructing the Egyptian pyramids . Open-seas navigation using the astrolabe and the compass started during the Age of Discovery in

5670-548: The Māori wahaika , the dalca –a sewn-plank canoe as used on Chiloe Archipelago, the curanto earth oven (Polynesian umu ) common in southern Chile, fishing techniques such as stone wall enclosures, palín –a hockey-like game– and other potential parallels. Some strong westerlies and El Niño wind blow directly from central-east Polynesia to the Mapuche region, between Concepción and Chiloe . A direct connection from New Zealand

5796-655: The Philippines and Indonesia . In the archeogenetic record, there are well-defined traces of this expansion that allow the path it took to be followed and dated with a degree of certainty. In the mid-2nd millennium BC, a distinctive culture appeared suddenly in north-west Melanesia, in the Bismarck Archipelago , the chain of islands forming a great arch from New Britain to the Admiralty Islands . This culture, known as Lapita , stands out in

5922-522: The Polynesian Voyaging Society to test the contentious question of how Polynesians found their islands. The team claimed to be able to replicate ancient Hawaiian double-hulled canoes capable of sailing across the ocean using strictly traditional voyaging techniques. In 1980, a Hawaiian named Nainoa Thompson invented a new method of non-instrument navigation (called the "modern Hawaiian wayfinding system"), enabling him to complete

6048-552: The United States in cooperation with six partner nations. OMEGA was developed by the United States Navy for military aviation users. It was approved for development in 1968 and promised a true worldwide oceanic coverage capability with only eight transmitters and the ability to achieve a four-mile (6 km) accuracy when fixing a position. Initially, the system was to be used for navigating nuclear bombers across

6174-440: The compass , charts, astronomical tables , the sextant (or an earlier instrument with the same role) and, in later phases of European exploration, chronometers . The interest shown by European navigators, such as James Cook and Andia y Varela was heightened by their lack of knowledge of environmental navigation techniques used by their European predecessors. Non-instrumental-based navigation had been carried out in many parts of

6300-700: The mariner's astrolabe first occurred in the Mediterranean during the Middle Ages. Although land astrolabes were invented in the Hellenistic period and existed in classical antiquity and the Islamic Golden Age , the oldest record of a sea astrolabe is that of Spanish astronomer Ramon Llull dating from 1295. The perfecting of this navigation instrument is attributed to Portuguese navigators during early Portuguese discoveries in

6426-431: The white tern and noddy tern fly out to sea in the morning to hunt fish, then return to land at night. Navigators seeking land sail opposite the birds' path in the morning and with them at night, especially relying on large groups of birds, and keeping in mind changes during nesting season. Harold Gatty suggested that long-distance Polynesian voyaging followed the seasonal paths of bird migrations . In The Raft Book ,

SECTION 50

#1732800983131

6552-400: The "index mirror" is fixed to the top of the index arm, over the pivot. As the index arm is moved, this mirror rotates, and the graduated scale on the arc indicates the measured angle ("altitude"). The second mirror, referred to as the "horizon glass", is fixed to the front of the frame. One half of the horizon glass is silvered and the other half is clear. Light from the celestial body strikes

6678-800: The 15th century. The Portuguese began systematically exploring the Atlantic coast of Africa from 1418, under the sponsorship of Prince Henry . In 1488 Bartolomeu Dias reached the Indian Ocean by this route. In 1492 the Spanish monarchs funded Christopher Columbus 's expedition to sail west to reach the Indies by crossing the Atlantic, which resulted in the Discovery of the Americas . In 1498,

6804-463: The Americas (called kūmara in Māori ), which have been radiocarbon-dated to 1000 CE, has been cited as evidence that Native Americans could have traveled to Oceania. The current thinking is that sweet potato was brought to central Polynesia circa 700 CE and spread across Polynesia from there, possibly by Polynesians who had traveled to South America and back. An alternative explanation posits biological dispersal ; plants and/or seeds could float across

6930-631: The Central Polynesia but have been attributed to trade. In accordance with Polynesian oral tradition, the geography of Polynesian navigation pathways is said to resemble the geometric qualities of an octopus with head centred on Ra'iātea (French Polynesia) and tentacles spread out across the Pacific. In oral tradition the octopus is known by various names such as Taumata-Fe'e-Fa'atupu-Hau (Grand Octopus of Prosperity), Tumu-Ra'i-Fenua (Beginning-of-Heaven-and-Earth) and Te Wheke-a-Muturangi (The Octopus of Muturangi ). Specific chronology of

7056-578: The Chumash and neighboring Tongva are unique among the indigenous peoples of North America, but similar in design to larger canoes used by Polynesians and Melanesians for deep-sea voyages. Tomolo'o , the Chumash word for such a craft, may derive from tumula'au / kumula'au , the Hawaiian term for the logs from which shipwrights carve planks to be sewn into canoes. The analogous Tongva term, tii'at ,

7182-628: The DCB, but with a 150-watt bulb instead of the 1,000-watt DCB bulb. In 1998, the Coast Guard replaced the AGA with a newer Vega rotating beacon . The New Dungeness Light Station historic district , a 8 acres (3.2 ha) area comprising the lighthouse, the keeper's quarters and three other contributing properties was added to the National Register of Historic Places in 1993. Henry Blake

7308-484: The Greenwich meridian to 180° east and west. Sydney , for example, has a longitude of about 151° east . New York City has a longitude of 74° west . For most of history, mariners struggled to determine longitude. Longitude can be calculated if the precise time of a sighting is known. Lacking that, one can use a sextant to take a lunar distance (also called the lunar observation , or "lunar" for short) that, with

7434-511: The Melanesian archeological record, with its large permanent villages on beach terraces along the coasts. Particularly characteristic of the Lapita culture is the making of pottery, including a great many vessels of varied shapes, some distinguished by fine patterns and motifs pressed into the clay. Between about 1300 and 900 BC, the Lapita culture spread 6,000 km (3,700 mi) farther to

7560-553: The North Pole to Russia. Later, it was found useful for submarines. Due to the success of the Global Positioning System the use of Omega declined during the 1990s, to a point where the cost of operating Omega could no longer be justified. Omega was terminated on September 30, 1997, and all stations ceased operation. LORAN is a terrestrial navigation system using low frequency radio transmitters that use

7686-576: The North, and, in another direction, from Easter Island, to the Hebrides (Vanuatu); that is, over an extent of sixty degrees of latitude, or twelve hundred leagues north and south, and eighty-three degrees of longitude, or sixteen hundred and sixty leagues east and west! How much farther in either direction its colonies reach is not known; but what we know already; in consequence of this and our former voyage, warrants our pronouncing it to be, though perhaps not

SECTION 60

#1732800983131

7812-808: The Pacific without any human contact. A 2007 study published in the Proceedings of the National Academy of Sciences examined chicken bones at El Arenal, Chile , near the Arauco Peninsula . The results suggested Oceania-to-America contact. The domestication of chickens originated in southern Asia, whereas the Araucana breed of Chile is thought to have been introduced to the Americas by Spaniards around 1500. The bones found in Chile were radiocarbon-dated to between 1304 and 1424, prior to

7938-454: The Philippines, north to parallel 39°, and hit the eastward Kuroshio Current which took its galleon across the Pacific. He arrived in Acapulco on October 8, 1565. The term stems from the 1530s, from Latin navigationem (nom. navigatio ), from navigatus , pp. of navigare "to sail, sail over, go by sea, steer a ship," from navis "ship" and the root of agere "to drive". Roughly,

8064-635: The Santa Cruz Islands; and Hipour of Puluwat navigating in the Caroline Islands ; and also conversations with Fe'iloakitau Kaho, Ve'ehala and Kaloni Kienga from Tonga ; Temi Rewi of Beru and Iotiabata Ata of Tarawa in the Gilbert Islands ; and Yaleilei of Satawal in the Caroline Islands. Anthropologist and historian Ben Finney built Nalehia , a 40-foot (12 m) replica of a Hawaiian double canoe . Finney tested

8190-481: The South Pacific became occupied, and citizenship and national borders became of international importance, this was no longer possible. People thus became trapped on islands with the inability to support them. Navigators travelled to small inhabited islands using wayfinding techniques and knowledge passed by oral tradition from master to apprentice, often in the form of song. Generally, each island maintained

8316-593: The Tuamotus or the Cook Islands to New Zealand might have followed the migration of the long-tailed cuckoo ( Eudynamys taitensis ), just as a voyage from Tahiti to Hawaiʻi would coincide with the track of the Pacific golden plover ( Pluvialis fulva ) and the bristle-thighed curlew ( Numenius tahitiensis ). It is also believed that Polynesians, like many seafaring peoples, kept shore-sighting birds. One theory

8442-766: The United States Lighthouse Society started the New Dungeness chapter and were able to secure a lease from the Coast Guard. Since September 1994, members of the New Dungeness Light Station Association have staffed the station 24 hours per day, 365 days per year, and tours are available to the general public between 9AM - 5PM every day. Navigation It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating

8568-495: The bridge wing for recording sight times. In practice, a wrist watch coordinated to the nearest second with the chronometer will be adequate. A stop watch, either spring wound or digital, may also be used for celestial observations. In this case, the watch is started at a known GMT by chronometer, and the elapsed time of each sight added to this to obtain GMT of the sight. All chronometers and watches should be checked regularly with

8694-551: The canoe in a series of sailing and paddling experiments in Hawaiian waters. At the same time, ethnographic research in the Caroline Islands in Micronesia brought to light the fact that traditional stellar navigational methods were still very much in everyday use there. The building and testing of proa canoes ( wa ) inspired by traditional designs, the harnessing of knowledge from skilled Micronesians , as well as voyages using stellar navigation, allowed practical conclusions about

8820-421: The civilian navigator on a merchant ship or leisure craft must often take and plot their position themselves, typically with the aid of electronic position fixing. While the military navigator will have a bearing book and someone to record entries for each fix, the civilian navigator will simply pilot the bearings on the chart as they are taken and not record them at all. If the ship is equipped with an ECDIS , it

8946-474: The conditions around them. Micronesian navigators created charts using the rib of coconut leaves attached to a square frame, with the curvature and meeting-points of the coconut ribs indicating the wave motion that was the result of islands standing in the path of the prevailing wind and the run of the waves. When European navigators first learnt of the navigational skills of Polynesians, they compared them to their own methods, which relied on, among other things,

9072-414: The cracks in the tower were so severe that the district's chief lighthouse engineer, Clarence Sherman, noting the structural instabilities, feared that the tower would topple. It was decided that year that the tower would be lowered to its current height of 63 feet (19 m). With the new tower dimensions, the original 3rd order fresnel lens was too large for the tower. To save costs, the lantern room from

9198-466: The decommissioned Admiralty Head lighthouse was removed and placed atop the shorter tower. The newly painted tower was relit with a revolving 4th order Fresnel lens. In the mid-1970s the Coast Guard decided to remove the Fresnel lens and test a DCB airport style beacon. The beacon only lasted a few years until it was replaced by a much smaller AGA-acrylic revolving beacon that provided the same range as

9324-718: The discovery and settlement of specific island groups within Eastern and Central Polynesia is hotly debated among archeologists, but a generally accepted timeline puts the initial settlement of the Cook Islands before 1000 AD. From this point, navigation branched out in all directions with Eastern Polynesia (including the Society Islands and the Marquesas Islands ) settled first followed by more remote regions such as Hawaii , Easter Island , and New Zealand peopled later. The pattern of settlement also extended to

9450-642: The documented arrival of the Spanish. DNA sequences taken were exact matches to the sequences of chickens from the same period in American Samoa and Tonga , both over 5000 miles (8000 kilometers) away from Chile. The genetic sequences were also similar to those found in Hawaiʻi and Easter Island , the closest Polynesian island, at only 2500 miles (4000 kilometers). The sequences did not match any breed of European chicken. Although this initial report suggested

9576-523: The east from the Bismarck Archipelago, until it reached as far as Tonga and Samoa . Lapita pottery persisted in places such as Samoa , Tonga , and Fiji for many years after its introduction to Western Polynesia but eventually died out in most of Polynesia due to the scarcity of clay. Although the production of ceramics did not travel beyond Western Polynesia, some ceramic materials have been recovered through archeological excavations in

9702-523: The equator, celestial navigation is simplified, given that the whole celestial sphere is exposed. Any star that passes through the zenith (overhead) moves along the celestial equator , the basis of the equatorial coordinate system . The Polynesians also used wave and swell formations to navigate. Many of the habitable areas of the Pacific Ocean are groups of islands (or atolls) in chains hundreds of kilometres long. Island chains have predictable effects on waves and currents. Navigators who lived within

9828-424: The extent of voyaging by Raiateans had diminished to the islands of eastern Polynesia. His grandfather and father had passed to Tupaia the knowledge as to the location of the major islands of western Polynesia and the navigation information necessary to voyage to Fiji , Samoa and Tonga . Tupaia was hired by Joseph Banks, the ship's naturalist, who wrote that Cook ignored Tupaia's chart and downplayed his skills as

9954-554: The former's death in the Philippines in 1521. The fleet of seven ships sailed from Sanlúcar de Barrameda in Southern Spain in 1519, crossed the Atlantic Ocean and after several stopovers rounded the southern tip of South America . Some ships were lost, but the remaining fleet continued across the Pacific making a number of discoveries including Guam and the Philippines. By then, only two galleons were left from

10080-426: The horizon or more preferably a star, each time the sextant is used. The practice of taking celestial observations from the deck of a rolling ship, often through cloud cover and with a hazy horizon, is by far the most challenging part of celestial navigation. Inertial navigation system (INS) is a dead reckoning type of navigation system that computes its position based on motion sensors. Before actually navigating,

10206-480: The index mirror and is reflected to the silvered portion of the horizon glass, then back to the observer's eye through the telescope. The observer manipulates the index arm so the reflected image of the body in the horizon glass is just resting on the visual horizon, seen through the clear side of the horizon glass. Adjustment of the sextant consists of checking and aligning all the optical elements to eliminate "index correction". Index correction should be checked, using

10332-669: The initial latitude and longitude and the INS's physical orientation relative to the Earth (e.g., north and level) are established. After alignment, an INS receives impulses from motion detectors that measure (a) the acceleration along three axes (accelerometers), and (b) rate of rotation about three orthogonal axes (gyroscopes). These enable an INS to continually and accurately calculate its current latitude and longitude (and often velocity). Advantages over other navigation systems are that, once aligned, an INS does not require outside information. An INS

10458-620: The late 1890s, Oscar Brown and Joseph Dunn served as station keepers. By 1994, the Dungeness Lighthouse was one of the few lighthouses in the United States to have a full-time keeper. Michelle and Seth Jackson and their dog Chicago were the last to hold the post of lighthouse keepers. In March 1994, the Coast Guard boarded up all the windows at the station, checked all the electrical equipment and left. Within months,

10584-653: The latitude of a place on Earth is its angular distance north or south of the equator . Latitude is usually expressed in degrees (marked with °) ranging from 0° at the Equator to 90° at the North and South poles. The latitude of the North Pole is 90° N, and the latitude of the South Pole is 90° S. Mariners calculated latitude in the Northern Hemisphere by sighting the pole star ( Polaris ) with

10710-418: The main guide for navigators because they could follow its exact points as it rose and set. Once the sun had set they would use the rising and setting points of the stars. When there were no stars because of a cloudy night or during daylight, a navigator would use the winds and swells as guides. Through constant observation, navigators were able to detect changes in the speed of their canoes, their heading, and

10836-448: The mainspring, and a special balance designed to compensate for temperature variations. A spring-driven chronometer is set approximately to Greenwich mean time (GMT) and is not reset until the instrument is overhauled and cleaned, usually at three-year intervals. The difference between GMT and chronometer time is carefully determined and applied as a correction to all chronometer readings. Spring-driven chronometers must be wound at about

10962-421: The modern revival of these skills, they are being recorded and published. Between about 3000 and 1000 BC speakers of Austronesian languages spread through the islands of Southeast Asia – most likely starting out from Taiwan , as tribes whose natives were thought to have previously arrived from mainland South China about 8000 years ago – into the edges of western Micronesia and on into Melanesia , through

11088-589: The most numerous, certainly by far the most extensive, nation upon earth. There is academic debate on the furthest southern extent of Polynesian expansion. The islands of New Zealand, along with a series of outlying islands, have been labelled 'South Polynesia' by New Zealand archaeologist Atholl Anderson . These islands include the Kermadec Islands , the Chatham Islands , the Auckland Islands and Norfolk Island . In each of these islands there

11214-544: The navigation of spacecraft themselves. This has historically been achieved (during the Apollo program ) via a navigational computer , an Inertial navigation system, and via celestial inputs entered by astronauts which were recorded by sextant and telescope. Space rated navigational computers, like those found on Apollo and later missions, are designed to be hardened against possible data corruption from radiation. Another possibility that has been explored for deep space navigation

11340-462: The navigator will have to rely on his skill in the manual and time-tested procedures. Celestial navigation systems are based on observation of the positions of the Sun , Moon , planets and navigational stars . Such systems are in use as well for terrestrial navigating as for interstellar navigating. By knowing which point on the rotating Earth a celestial object is above and measuring its height above

11466-521: The navigator's position compared to known locations or patterns. Navigation, in a broader sense, can refer to any skill or study that involves the determination of position and direction . In this sense, navigation includes orienteering and pedestrian navigation. In the European medieval period, navigation was considered part of the set of seven mechanical arts , none of which were used for long voyages across open ocean. Polynesian navigation

11592-476: The navigators with a sense of latitude , so that they could sail with the prevailing wind, before turning east or west to reach the island that was their destination. Some star compass systems specify as many as 150 stars with known bearings, though most systems have only a few dozen (illustration at right). The development of sidereal compasses has been studied and hypothesized to have developed from an ancient pelorus instrument. For navigators near

11718-623: The north of Samoa to the Tuvaluan atolls, with Tuvalu providing a stepping stone to the founding of Polynesian Outlier communities in Melanesia and Micronesia . The natives of Easter Island likely originated from Mangareva. They discovered the island by using the flight path of the sooty tern. When the first European to visit the island, Jacob Roggeveen, landed on Easter Island, he found no evidence of navigation. Instead, he noticed that there were not enough trees to build seaworthy canoes and

11844-579: The object in the Museum's collection documentation indicates no reference to Polynesian influences." Oral history describes Ui-te-Rangiora , around the year 650, leading a fleet of Waka Tīwai south until they reached, "a place of bitter cold where rock-like structures rose from a solid sea". The brief description might match the Ross Ice Shelf or possibly the Antarctic mainland , but may be

11970-405: The observer's horizon, the navigator can determine his distance from that subpoint. A nautical almanac and a marine chronometer are used to compute the subpoint on Earth a celestial body is over, and a sextant is used to measure the body's angular height above the horizon. That height can then be used to compute distance from the subpoint to create a circular line of position. A navigator shoots

12096-467: The original authors extended and elaborated their findings, concluding: This comprehensive approach demonstrates that the examination of modern chicken DNA sequences does not contribute to our understanding of the origins of Chile's earliest chickens. Interpretations based on poorly sourced and documented modern chicken populations, divorced from the archeological and historical evidence, do not withstand scrutiny. Instead, this expanded account will confirm

12222-661: The original seven. The Victoria led by Elcano sailed across the Indian Ocean and north along the coast of Africa, to finally arrive in Spain in 1522, three years after its departure. The Trinidad sailed east from the Philippines, trying to find a maritime path back to the Americas , but was unsuccessful. The eastward route across the Pacific, also known as the tornaviaje (return trip) was only discovered forty years later, when Spanish cosmographer Andrés de Urdaneta sailed from

12348-476: The path a radar object should follow on the radar display if the ship stays on its planned course. During the transit, the navigator can check that the ship is on track by checking that the pip lies on the drawn line. Global Navigation Satellite System or GNSS is the term for satellite navigation systems that provide positioning with global coverage. A GNSS allow small electronic receivers to determine their location ( longitude , latitude , and altitude ) within

12474-520: The pre-Columbian age of the El Arenal remains and lend support to our original hypothesis that their appearance in South America is most likely due to Polynesian contact with the Americas in prehistory. In 2005, a linguist and an archeologist proposed a theory of contact between Hawaiians and the Chumash people of Southern California between 400 and 800 CE. The sewn-plank canoes crafted by

12600-429: The radar scanner. When a vessel (ship or boat) is within radar range of land or fixed objects (such as special radar aids to navigation and navigation marks) the navigator can take distances and angular bearings to charted objects and use these to establish arcs of position and lines of position on a chart. A fix consisting of only radar information is called a radar fix. Types of radar fixes include "range and bearing to

12726-401: The rafts the natives were using were not seaworthy either. The archeological record supports oral histories of the first peopling of region including both the timing and geographical origins of Polynesian society. Polynesian navigation relies heavily on constant observation and memorization. Navigators have to memorize where they have sailed from in order to know where they are. The sun was

12852-517: The rear section of the fuselage, whereas most US aircraft enclosed the antenna in a small teardrop-shaped fairing. In navigational applications, RDF signals are provided in the form of radio beacons , the radio version of a lighthouse . The signal is typically a simple AM broadcast of a morse code series of letters, which the RDF can tune in to see if the beacon is "on the air". Most modern detectors can also tune in any commercial radio stations, which

12978-468: The reasons for the presence of the Polynesians in such isolated and scattered parts of the Pacific. According to Andrew Sharp , the explorer Captain James Cook , already familiar with Charles de Brosses 's accounts of large groups of Pacific islanders who were driven off course in storms and ended up hundreds of miles away with no idea where they were, encountered in the course of one of his own voyages

13104-469: The reflections of shallow water made on the undersides of clouds. It is thought that the Polynesian navigators may have measured sailing time between islands in "canoe-days". The energy transferred from the wind to the sea produces wind waves. The waves that are created when the energy travels down away from the source area (like ripples) are known as swell. When the winds are strong at the source area,

13230-409: The same frequency range, called CHAYKA . LORAN use is in steep decline, with GPS being the primary replacement. However, there are attempts to enhance and re-popularize LORAN. LORAN signals are less susceptible to interference and can penetrate better into foliage and buildings than GPS signals. Radar is an effective aid to navigation because it provides ranges and bearings to objects within range of

13356-412: The same time each day. Quartz crystal marine chronometers have replaced spring-driven chronometers aboard many ships because of their greater accuracy. They are maintained on GMT directly from radio time signals. This eliminates chronometer error and watch error corrections. Should the second hand be in error by a readable amount, it can be reset electrically. The basic element for time generation

13482-400: The screen that is parallel to the ship's course, but offset to the left or right by some distance. This parallel line allows the navigator to maintain a given distance away from hazards . The line on the radar screen is set to a specific distance and angle, then the ship's position relative to the parallel line is observed. This can provide an immediate reference to the navigator as to whether

13608-445: The seasons. Each star has a specific declination , and can give a bearing for navigation as it rises or sets. Polynesian voyagers would set a heading by a star near the horizon, switching to a new one once the first rose too high. A specific sequence of stars would be memorized for each route. The Polynesians also took measurements of stellar elevation to determine their latitude. The latitudes of specific islands were also known, and

13734-429: The seaworthiness and handling capabilities of traditional Polynesian canoes and allowed a better understanding of the navigational methods that were likely to have been used by the Polynesians and of how they, as people, were adapted to seafaring. Recent re-creations of Polynesian voyaging have largely used Micronesian methods and the teachings of a Micronesian navigator, Mau Piailug . In 1973, Ben Finney established

13860-511: The ship is on or off its intended course for navigation. Other techniques that are less used in general navigation have been developed for special situations. One, known as the "contour method," involves marking a transparent plastic template on the radar screen and moving it to the chart to fix a position. Another special technique, known as the Franklin Continuous Radar Plot Technique, involves drawing

13986-474: The sky also could be recognised as resulting from the presence of lagoons or shallow waters, as deep water was a poor reflector of light while the lighter colour of the water of lagoons and shallow waters could be identified in the reflection in the sky. In Eastern Polynesia, navigators sailing from Tahiti to the Tuamotus would sail directly east towards Anaa atoll, which has a shallow lagoon that reflects

14112-413: The swell is larger. The longer the wind blows, the longer the swell lasts. Because the swells of the ocean can remain consistent for days, navigators relied on them to carry their canoe in a straight line from one house (or point) on the star compass to the opposite house of the same name. Navigators were not always able to see stars; because of this, they relied on the swells of the ocean. Swell patterns are

14238-809: The table. The practice of navigation usually involves a combination of these different methods. By mental navigation checks, a pilot or a navigator estimates tracks, distances, and altitudes which will then help the pilot avoid gross navigation errors. Piloting (also called pilotage) involves navigating an aircraft by visual reference to landmarks, or a water vessel in restricted waters and fixing its position as precisely as possible at frequent intervals. More so than in other phases of navigation, proper preparation and attention to detail are important. Procedures vary from vessel to vessel, and between military, commercial, and private vessels. As pilotage takes place in shallow waters , it typically involves following courses to ensure sufficient under keel clearance , ensuring

14364-418: The technique of "sailing down the latitude" was used. That is, Polynesians navigated by the stars through knowledge of when particular stars, as they rotated through the night sky, would pass over the island to which the voyagers were sailing. Also knowledge that the movement of stars over different islands followed a similar pattern (that is, all the islands had a similar relationship to the night sky) provided

14490-462: The time interval between radio signals received from three or more stations to determine the position of a ship or aircraft. The current version of LORAN in common use is LORAN-C, which operates in the low frequency portion of the EM spectrum from 90 to 110 kHz . Many nations are users of the system, including the United States , Japan , and several European countries. Russia uses a nearly exact system in

14616-411: The time of day or night. Polynesian navigators thus employed a wide range of techniques including the use of the stars, the movement of ocean currents and wave patterns, the patterns of bioluminescence that indicated the direction in which islands were located, the air and sea interference patterns caused by islands and atolls , the flight of birds, the winds and the weather. Certain seabirds such as

14742-466: The vast Polynesian Triangle , using outrigger canoes or double-hulled canoes. The double-hulled canoes were two large hulls, equal in length, and lashed side by side. The space between the paralleled canoes allowed for storage of food, hunting materials, and nets when embarking on long voyages. Polynesian navigators used wayfinding techniques such as the navigation by the stars, and observations of birds, ocean swells, and wind patterns, and relied on

14868-449: The voyage from Hawaiʻi to Tahiti and back. In 1987, Matahi Whakataka-Brightwell and his mentor Francis Cowan sailed from Tahiti to New Zealand without instruments in the waka Hawaiki-nui . In 1978, the Hōkūleʻa was capsized en route to Tahiti. Eddie Aikau, a world champion surfer, and part of the crew, attempted to paddle his surfboard to the nearest island to find help. However, Aikau

14994-529: The water surface, and originates from islands. It is used by Polynesians to reorient themselves out at sea or to find new islands. There is currently no evidence of historic Polynesian navigators using navigational devices on board vessels. However, the Micronesian people of the Marshall Islands have a history of using a stick chart onshore, to serve as spatial representations of islands and

15120-474: The world, having occurred in the Indian Ocean, the Mediterranean and the European Atlantic. The details of these techniques varied to suit the latitude and the usual weather patterns. One such difference is that the zone in which most Polynesian voyaging was carried out was within 20° of the equator, so rising and setting stars did so at an angle that was close to vertical relative to the horizon. This

15246-524: Was a 2000 kilometer boundary around Antarctica that Polynesian peoples may not have crossed. Descriptions of a shard of early Polynesian pottery buried on the Antipodes Islands are unsubstantiated, and the Museum of New Zealand Te Papa Tongarewa , where it was supposedly stored, has stated that "The Museum has not been able to locate such a shard in its collection, and the original reference to

15372-587: Was first lit in 1857 and was the second lighthouse established in the Washington territory, following the Cape Disappointment Light of 1856. Originally, the lighthouse was a 1½-story duplex with a 100-foot (30 m) tower rising from the roof. The tower was painted black on the top half and white on the lower section. Over time, the tower developed structural cracks, most likely from a combination of earthquakes and weather erosion. In 1927,

15498-419: Was never seen again. The crew was later rescued regardless of the fact that Aikau didn't make it to the nearest island. In New Zealand, a leading Māori navigator and ship builder was Hector Busby , who was also inspired and influenced by Nainoa Thompson and Hokulea's voyage there in 1985. In 2008, an expedition starting in the Philippines sailed two modern James Wharram -designed catamarans loosely based on

15624-412: Was severely limited in the field of exploration, and that as a result, the settlement of Polynesia had been the result of luck, random island sightings, and drifting, rather than as organized voyages of colonization. Thereafter, the oral knowledge passed down for generations allowed for eventual mastery of traveling between known locations. Sharp's reassessment caused a huge amount of controversy and led to

15750-495: Was the case with Loran C , its primary use was for ship navigation in coastal waters. Fishing vessels were major post-war users, but it was also used on aircraft, including a very early (1949) application of moving-map displays. The system was deployed in the North Sea and was used by helicopters operating to oil platforms . The OMEGA Navigation System was the first truly global radio navigation system for aircraft, operated by

15876-507: Was the lighthouse's first keeper. The USCG coastal buoy tender WLM-563 Henry Blake based in Everett, Washington is named after him. Franklin Tucker, the temporary keeper from 1857 to 1858, replaced Blake in 1873. He remained in charge from April of that year until December 1882, when he was transferred to Ediz Hook Light Station and replaced by Amos Morgan, who served until March 1896. In

#130869