Determination Of Longitude Research Articles

Mishaps in the Land van Eendracht: Exploring the Cause of Zuytdorp’s Wrecking

Zuytdorp is one of four known Dutch East India Company shipwrecks off the western Australian coast. Believed to have foundered in the fall of 1712, its wreck site was located in 1927 on a remote stretch of the central western Australian coast. Since its identification in 1958, the site has been investigated during several archaeological expeditions. The cause of Zuytdorp’s wrecking, however, has never been properly assessed. Some researchers assume the ship crashed into shore due to an inaccurate longitude determination. Others believe the ship reached the Australian coastline safely and foundered due to a storm or other mishap. This study will use various lines of evidence to answer the question of how Zuytdorp wrecked. These include an assessment of contemporary cartographic and navigational knowledge, charts that would have been available on the vessel, coastal visibility, and signs that ships were nearing land as found in contemporary ship logs. It will be shown that Zuytdorp’s officers had access to the necessary cartographic information in order to navigate the Indian Ocean and Western Australian coastline, that there were numerous warning signs the vessel was nearing the coast and various measures taken to avoid a collision, and that meteorological conditions at the wreck site likely drove the ship ashore. Through a thorough analysis of these lines of evidence, it will be demonstrated that a sudden and unexpected encounter with the shore is an unlikely scenario. Instead, Zuytdorp could have reached the Australian coastline intentionally and most likely wrecked due to a storm.

Differential Rotation of CoRoT Stars and a Kepler Binary Star from Starspot Transit Mapping

Abstract While direct magnetic field measurements are rare for slowly rotating stars, spots observed during planetary transits provide a potential indicator of magnetic activity on stellar surfaces. Moreover, the rotation of the stellar surface can be probed by monitoring the spots’ position with time in subsequent transits. This study investigates the dynamic interplay of rotational shear and stellar rotation rate in six stars of spectral types F to M, all hosting exoplanets observed by the CoRoT space mission, except for one binary star from Kepler. The analysis, facilitated by the ECLIPSE code, unveils the physical properties of stellar spots, including radius, intensity, temperature, and position. The five CoRoT stars exhibit spot characteristics consistent with those observed in solar type stars. The determination of a spot longitude during different transits allows for the inference of the star’s differential rotation profile, revealing a decreasing trend of rotational shear with the mean stellar rotation period, given by Δ Ω ∝ P ¯ − 0.9 . This implies that, at least for slow rotators (mean rotation period >5 days), as stars age, their differential rotation decreases. Additionally, the six stars analyzed here seem to fall into two categories, according to their spot flux deficit: those with ΔF spot > 0.005 and those with ΔF spot < 0.002.

Geographic longitude in Latin Europe during the twelfth and thirteenth centuries

This article surveys surviving evidence for the determination of geographic longitude in Latin Europe in the period between 1100 and 1300. Special consideration is given to the different types of sources that preserve longitude estimates as well as to the techniques that were used in establishing them. While the method of inferring longitude differences from eclipse times was evidently in use as early as the mid-twelfth century, it remains doubtful that it can account for most of the preserved longitudes. An analysis of 89 different estimates for 30 European cities indicates a high degree of accuracy among the longitudes of English cities and a conspicuous displacement eastward (by 5°–7;30°) shared by most longitudes of cities in Italy and France. In both cases, the data suggest a high level of interdependence between estimates for different cities in the same geographic region, although the means by which these estimates were arrived at remain insufficiently known.

Circles, Clocks, Ships, and Wires: Meridian Circles within Innovative Assemblages in 19th-Century America

Driven by needs to map an expanding nation as well as by pure astronomical inquiry, nearly 50 meridian circles were installed in 19th-century U.S. observatories. In the 1840s, U.S. astronomers used meridian circles in conjunction with chronometers on fast steamships to ascertain transatlantic longitude differences. Simultaneously, they devised methods of using meridian circles with newly invented telegraph technologies, which revolutionized longitude determination, productivity of data collection within observatories, and distribution of time signals. 19th-century U.S. astronomers and artisans also designed improvements to meridian circles themselves; by century end, U.S.-based instrument makers dominated the domestic meridian circle market over English and German artisans.

RESULTS OF SEMI-NATURAL TESTS OF THE AUTONOMOUS DETERMINATION OF THE VEHICLE LONGITUDE AND LATITUDE

Navigation parameters such as vehicle heading, linear speed and latitude and longitude are determined today, as a rule,using satellite navigation systems. However, there is a need for autonomous determination of navigation parameterswhen satellite navigation system signals are unavailable for one reason or another. For example, satellite navigationsystem signals can be jammed by electromagnetic countermeasures.Autonomous systems for determining the vehicle navigation parameters are inertial navigation systems, the basis ofwhich is the double integration of signals from accelerometers, as well as the integration of signals from gyroscopes toform one or another coordinate system, if we are talking about strapdown inertial navigation systems (SINS).Integration of the output signals of accelerometers and gyroscopes, which contain errors, leads to the accumulation ofSINS errors. To increase accuracy, SINS are integrated, for example, with satellite navigation systems. However, suchsystems cease to be completely autonomous.The article uses the method of autonomous determination of vehicle latitude and longitude, which is a new method ininertial navigation. The method is based on the strapdown inertial technology, which, unlike the standard methods usedin SINS, does not use the integration of the output signals of accelerometers and gyroscopes. To determine the angles oflatitude and longitude, the signals of the gyroscopes included in the inertial measurement unite (IMU) are used.As a result of a semi-natural experiment, the efficiency of the method of autonomous determination of latitude andlongitude was verified. Flight data of a small-sized aircraft were used for experimental verification. The data containedinformation about the angles of the heading, pitch, roll of the aircraft, the output signals of three micromechanicalgyroscopes, three micromechanical accelerometers, information about latitude, longitude and altitude measured by thereceiver of the satellite navigation system, as well as information about the horizontal and vertical components of speedand current time. Plots of calculated values of latitude and longitude and values measured using the receiver of thesatellite navigation system are given. From the given plots and tables, it can be seen that from a certain time, thecalculated values coincide with the "reference" ones, which confirms the efficiency of the method of autonomousdetermination of latitude and longitude.

IN SEARCH OF THE <italic>PROMONTORIUM SOMNII</italic>

In 1863-1866, the French writer Victor Hugo wrote a long text in which he related a visit he made in 1834 at Paris Observatory, where François Arago showed him the Sun rising on the Moon. Amongst the lunar features progressively illuminated by the Sun, he noticed <italic>Promontorium Somnii</italic> and, impressed by this poetic name, he used it as the title of his text. We show that <italic>Promontorium Somnii</italic>, which has since disappeared from lunar terminology, was introduced in 1686 by Jean-Dominique Cassini as one of the benchmarks used for determination of longitudes by the observation of lunar eclipses. There have been questions about the location of <italic>Promontorium Somnii</italic> on the surface of the Moon, and we show that it is a corner of a better known feature mapped in 1651 by Riccioli, <italic>Palus Somni</italic>. We give a translation of the 'astronomical' part of Hugo's text and some comments about the determination of longitudes using lunar eclipses.

The Method for Autonomous Determination of Longitude and Latitude of a Moving Object

The Method for Autonomous Determination of Longitude and Latitude of a Moving Object

Amerigo Vespucci's Contribution to the Modernization of Cartographic Representation

In 2019, the Rostock University Library acquired the report by Amerigo Vespucci (1454–1512) on transatlantic discoveries, which was published in 1505 by the city secretary Hermann Barckhusen (c 1460–1528/29) in Rostock under the title “Epistola Albericij. De novo mundo” [1505] and, unlike other editions, was published with a map. The special feature of the map is that it is the oldest map with a globular projection. Vespucci reported in a letter dated July 18, 1500 to Lorenzo di Pierfrancesco de' Medici about his voyage 1499–1500, which is an important source for the fact that his longitude determinations contributed to the realization that the transatlantic discoveries were about a continent. The letter also contains evidence that Vespucci was the originator of the globular projection. This marked the beginning of a departure from ancient traditions regarding the projections for world maps. To enable the combined representation of the “old world” together with the “new world” in one map, Vespucci's projection was later modified into an oval map, which was used, for example, by Franzesco Rosselli, Sebastian Münster and Abraham Ortelius.

A (NOT SO) BRIEF HISTORY OF LUNAR DISTANCES: LUNAR LONGITUDE DETERMINATION AT SEA BEFORE THE CHRONOMETER

Longitude determination at sea gained increasing commercial importance in the late Middle Ages, spawned by a commensurate increase in long-distance merchant shipping activity. Prior to the successful development of an accurate marine timepiece in the late-eighteenth century, marine navigators relied predominantly on the Moon for their time and longitude determinations. Lunar eclipses had been used for relative position determinations since Antiquity, but their rare occurrences precludes their routine use as reliable way markers. Measuring lunar distances, using the projected positions on the sky of the Moon and bright reference objects—the Sun or one or more bright stars—became the method of choice. It gained in profile and importance through the British Board of Longitude's endorsement in 1765 of the establishment of a <italic>Nautical Almanac</italic>. Numerous 'projectors' jumped onto the bandwagon, leading to a proliferation of lunar ephemeris tables. Chronometers became both more affordable and more commonplace by the mid-nineteenth century, signaling the beginning of the end for the lunar distance method as a means to determine one's longitude at sea.

EUROPEAN LONGITUDE PRIZES. I: LONGITUDE DETERMINATION IN THE SPANISH EMPIRE

Following Columbus' voyages to the Americas, Castilian (Spanish) and Portuguese rulers engaged in heated geopolitical competition, which was eventually reconciled through a number of treaties that divided the world into two unequal hemispheres. However, the early-sixteenth-century papal demarcation line was poorly defined. Expressed in degrees with respect to a vague reference location, determination of longitude at sea became crucial in the nations' quest for expanding spheres of influence. In Spain, King Philip II and his son, Philip III, announced generous rewards for those whose solutions to the longitude problem performed well in sea trials and which were suitable for practical implementation. The potential reward generated significant interest from scientist-scholars and opportunists alike. The solutions proposed and the subset taken to sea provided important physical insights that still resonate today. None of the numerous approaches based on compass readings ('magnetic declination') passed the exacting sea trials, but the brightest sixteenth-century minds already anticipated that lunar distances and the use of marine timepieces would eventually enable more precise navigation. With most emphasis in the English-language literature focused on longitude solutions developed in Britain, France and the Low Countries, the earlier yet ground-breaking Spanish efforts have, undeservedly, largely been forgotten. Yet, they provided a firm basis for the development of an enormous 'cottage industry' that lasted until the end of the eighteenth century.

Introducing theodolites for mapping in Norway

ABSTRACT Christopher Hansteen, professor of applied mathematics at the University of Oslo, was appointed as a part-time director of geodesy at the Geographical Survey of Norway in 1817. He quickly realized that previous measurements of angles using geographical circles did not produce data of required quality for geodetic surveying. Using archival sources, the article describes how Hansteen acquired a theodolite from Germany and applied it to demonstrate to the National Assembly (Storting) that investment in new instruments for the Survey was required. With funds granted in 1824, he ordered theodolites, sextants and chronometers from German instrument makers. He conducted a field operation in 1827 in preparation for a first-time survey and mapping of the entire coast of Northern Norway. The article draws on observation logbooks to reconstruct the triangle arc established with the new theodolites between 1828 and 1842. The triangulation stations served as reference points for plane table mapping. Map orientation and geodetic coordinates were controlled by astronomical observations of latitude and chronometer determinations of longitude at two temporary observatories and through selected field observations. The resulting ten maps were the first production released to the public by the Geographical Survey of Norway.

Programa computacional científico para a elaboração automática de listas de estrelas para astronomia de posição (LEDAP): revisão dos conceitos e exemplo de aplicação

É apresentado o LEDAP, programa computacional científico que elabora automaticamente listas de estrelas para a determinação astronômica de precisão da latitude (método de Sterneck), longitude (método das distâncias zenitais absolutas) e azimute (método das estrelas em circum-elongação). As aplicações das listas nas práticas de Astronomia de Posição possibilitam a rápida obtenção de coordenadas astronômicas e respectivos desvios-padrões. O conhecimento das coordenadas astronômicas e geodésicas (juntamente com as precisões) de um ponto permite o observador estimar pelo método astrogeodésico as componentes meridiana (ξ), 1° vertical (η) e o desvio da vertical (i), bem como, os respectivos desvios-padrões por propagação de covariâncias. Neste trabalho, a partir do uso de um teodolito de leitura direta de 1” e de um receptor de dupla frequência foram obtidas as coordenadas astronômicas e geodésicas (posicionamento relativo estático) de um pilar de concreto localizado na UNESP, câmpus Presidente Prudente/SP, bem como, as componentes e o desvio, sendo ξ = 3,3339 ± 3,3323”, η = –54,8849 ± 4,5255” e i = 54,9861 ± 4,5217”. Verificou-se que devido às precisões das coordenadas astronômicas serem inferiores às geodésicas, as precisões das componentes e do desvio foram da ordem de 4,5”, independentemente do método de posicionamento por satélites utilizado, com exceção do Posicionamento por Ponto Simples (PPS) que degradou as estimativas.

COOK'S THIRD VOYAGE TO THE PACIFIC AND EARLY SCIENTIFIC ASTRONOMY ON THE NORTH-WESTERN COAST OF AMERICA: THE SOJOURN AT NOOTKA SOUND IN APRIL 1778

Between 1768 and 1778 England's premier maritime explorer, James Cook, made three much-published and very successful expeditions to the Pacific. Astronomy played a vital role in navigation and coastal cartography, and consequently there were astronomers on all three Pacific expeditions. On the final voyage Cook would lose his life in Hawaii, but not before exploring the north-western coast of the American continent and visiting Nootka Sound on the western shores of Vancouver Island. In this paper we review the challenge of accurately determining latitude and longitude in the eighteenth century; provide biographical information about the three astronomers on Cook's Third Voyage (Cook, King and Bayly); examine the range of astronomical instruments used during the Voyage, and the associated instrument-makers; describe the various types of astronomical observations made for latitude and longitude determinations; and review the observations that were made at Nootka Sound during the 3-week stopover of the <italic>Resolution</italic> and <italic>Discovery</italic> in April 1778.

TOKOH FALAK MINANGKABAU (STUDI PEMIKIRAN SAADOEDDIN DJAMBEK DAN TAHIR JALALUDDIN)

&lt;p&gt;&lt;em&gt;This paper talks about the contribution of the Minangkabau Falak figures about dawn in Indonesia. At this time of dawn in Indonesia which is used as a reference or guideline of the Ministry of Religion that is the result of the thoughts and ijtihad of the previous scholars who are still in use today for the height and position of the sun at the time of the dawn of Sadiq -200. The clerics and celestial figures who be ijtihad about dawn with the -200 position came from Minangkabau namely Saadoeddin Djambek which is famous for the books of prayer and fasting in the polar regions. Saadoeddin djambek set -200 by quoting the opinion of his teacher, Sheikh Muhammad Tahir Jalaluddin al-Minangkabawi about determining the prayer time in Pati Kiraan and Nukhbah at-Taqrîrât fîHisâb al-Auqât was Samt al-Qiblah bi al-Lughâritmât. Determination of the height of the sun at the -200 position is based on geographical observations and considerations due to the factor of Indonesia that is close to the equator and influenced by astronomical data used, solar height and its correction as well as the determination of latitude and longitude.&lt;/em&gt;&lt;em&gt;&lt;/em&gt;&lt;/p&gt;

Kyoto and the heavens: setting Japan’s center of time

Why did scholars in mid-nineteenth century Japan assume that the prime meridian should run through Kyoto – positioning the city not only as the center of Japan but also of the entire world? Tracing the close connections between longitude determination, astronomical time measurement, and calendar compilation, this article argues that the making of Kyoto-centered place was rooted in the use of astronomical time as a tool for analyzing celestial and geographical space. This article first shows that the existence of a prime meridian on Japanese maps was the result of astronomical timekeeping practices used by an early nineteenth-century surveyor, Inō Tadataka. It then traces the decision to draw the prime meridian specifically through Kyoto to various centuries-old calendrical conventions, the astronomical work of Shibukawa Shunkai, and the metaphysics of seventeenth-century philosopher Yamazaki Ansai. The article emphasizes the role that practices of measurement, calculation, and observation played in the shaping of a map, the appearance of which eventually manifested the idea of the place it purportedly represents.

Twentieth-Century Longitude: When Greenwich Moved

By the beginning of the twentieth century, the meridian passing though the Royal Observatory at Greenwich had become a near-universal reference for place and time. It was the zero of longitude. But our current standard of zero longitude is about 100 metres away from the original. That mobility needs historical context: Greenwich began to move in the years after the First World War, when wireless techniques for the astronomical determination of longitude and the standardisation of time were developed, and has carried on moving ever since. In this article, I describe how twentieth-century techniques for the determination of longitude not only brought improved precision but also led to fundamental changes in our long-standing conventions of longitude. And I show how – despite its mobility – our current standard of zero longitude continues to respect the original.

Machine learning predicts home prices

In 1714, the British Parliament passed the Longitude Act, which offered serious money to anyone who could devise a practical method to measure longitude at sea. While the determination of longitude might seem a trivial thing in today's world of smartphones and GPS satellites, at the time it was an immense technical challenge. It took many years, but the strategy worked, leading to the development of the marine chronometer, a handheld mechanical marvel that undoubtedly saved the lives of countless sailors.

Rotating Poles, Shifting Angles and the Use of Geometry

In The Sea-Mans Kalendar (1636 [1638?]), Henry Bond predicted that magnetic declination would be 0 degrees in 1657, and would then increase westerly for (at least) 30 years. Based on these predictions, Bond went on to claim in The Longitude Found (1676) that, by using his model of magnetism, he can offer a technique for determining longitude. This paper offers an assessment of Bond's method for longitude determination and critically evaluates Thomas Hobbes's so-far neglected response to Bond's proposal in Decameron physio-logicum (1678), in which Hobbes complains about what he takes to be Bond's implicit natural philosophy and about his use of spherical trigonometry.

Prizes, patents and the search for longitude

The 1714 Longitude Act created the Board of Longitude to administer a large monetary prize and progress payments for the precise determination of a ship's longitude. However, the prize did not prohibit patenting. We use a new dataset of marine chronometer inventors to show that the propensity to patent was high. We argue that while the prize spurred entry by key inventors, and progress payments facilitated research investment in an area of significant social value, patents promoted disclosure. Our findings highlight the importance of complementarities between prize and patent-based incentives in the design of innovation inducement contests.

Digital astro-geodetic camera system for the measurement of the deflections of the vertical: tests and results

ABSTRACTThis study introduces the new results of a novel low-cost digital zenith camera system operated in Turkey that uses astronomical and geodetic instrumentation. Currently, it is possible to determine deflections of the vertical (DoV) components by using a vast amount of information gathered from geo-referenced star images, tilt measurements, and Global Navigation Satellite System technology. This new design of an astro-geodetic camera system is used for calculating DoV components with 12 independent solutions on a test station in Istanbul, and additional observations were performed to investigate the external accuracy of the system on a test network. A specific leveling method is developed to align system toward the zenithal direction. The final results of the observations on a test station located in Istanbul indicate that the accuracy of the system is about ±0.19 arc-seconds in latitude and ±0.28 arc-seconds in longitude determination. The system has been further tested on a network with 4 control points that have averagely 20 km baselines. At the test network, the root mean square of the average value of the vertical deflections is calculated as ±0.36 arc-seconds. Furthermore, DoV components are compared with the values that are calculated using global geopotential models.