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Marine chronometer

About: Marine chronometer is a(n) research topic. Over the lifetime, 116 publication(s) have been published within this topic receiving 633 citation(s).
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Journal ArticleDOI
Abstract: T I lHE scientific community dealing with earth characteristics, marine and air navigation, and modern concepts of national defense is vitally concerned with longitudinal ties between continents. Expanded interest in modern geodesy has resulted particularly from research programs in developing intercontinental guided missiles and earth-circling satellites. The art of navigation has always been the most practical application of longitude, but in this the art does not require any high degree of precision. Concomitant to the age of exploration and rapid expansion of water-borne traffic was the urgent demand for a means of determining longitude at sea. Beginning with Harrison's chronometer, steady refinements were made until modern times, when continental ties are possible with the aid of telegraph and radio. Aside from navigational considerations, several purely scientific requirements involve the precise determination of longitude with reference to a standard meridian, such as Greenwich. The astronomer requires an accurate position for the time coordination of world-wide astronomical observations; the geophysicist needs longitudes of the highest precision in his studies of the drift of continents; and, finally, the geodesist desires to place all triangulation datums as closely as possible in their proper relation one with the other. Longitudinal studies, no matter how localized in place or how distant in time, have an important bearing on the subject. In celebrating the sesquicentennial of the United States Coast and Geodetic Survey during 1957, it is fitting to recall the Survey's contribution to the establishment of precise longitude in the United States. Early in the history of this bureau the need became apparent for a precise tie between some main-scheme triangulation stations in the United States and the meridians of any and all of the European observatories. The Harvard Observatory at Cambridge was adopted for the point of origin in the United States and in due time was tied to Greenwich by the method discussed in this paper. The second superintendent of the Coast Survey, Alexander Dallas Bache, was well aware of the difficulties other nations had encountered in fixing the

86 citations

01 Jan 1997
Abstract: The history of the Royal Observatory, Greenwich has been revised to coincide with the Millenium. Color illustrations and updated text tell the story of Greenwich from its foundations in 1676 to its present status as Longitude 0, the world's Prime Meridian for measuring longitude and time. The book covers the importance of longitude for navigation and traces the history of Greenwich Time, the basis of universal time-keeping. The book is co-published with the National Maritime Museum, where Derek Howse was the former Head of Navigation and Astronomy.

40 citations

15 Mar 2005
Abstract: A non-volatile memory card is described, which comprises a chronometer powered by an autarkic, card-internal power supply with a long-term energy store. The chronometer is connected to a card internal controller, such that the chronometer can provide the current time to the controller independent of a host system.

35 citations

25 Apr 1980
Abstract: The invention relates to a detached escapement which preferably does not require oil to be applied to the escape wheel. The escapement has an escape wheel (10;30), a balance wheel and a pivoted lever (14;37) arranged so that during each movement of the balance wheel in one direction of rotation an impulse is applied direct to an element (25;33) attached to the balance wheel. During each movement of the balance wheel in the other direction of rotation it is preferred that an impulse is applied to the balance wheel via the pivoted lever. The escapement may be used in a watch, clock or chronometer.

34 citations

Journal ArticleDOI
Abstract: Popular accounts of scientific discoveries diverge from scholarly accounts, stripping off hedges and promoting short-term social consequences. This case study illustrates how the “horse-race”framing of popular accounts devalues the collective sharing, challeng ing, and extending of scientific work. In her best-selling Longitude, Dava Sobel (1996) depicts John Harrison’s 18th-century invention of a marine chronometer, a groundbreaking precision instrument that eventually allowed sailors to calculate their longitude at sea, as an unequal race with Harrison as beleaguered hero. Sobel represents the demands of the Board of Longitude to test and replicate the chronometer as the obstructionist machinations of an academic elite. Her framing underreports the feasibility of the chronometer and its astronomical rival, the lunar distance method, which each satisfied different criteria. That readers accept Sobel’s framing is indicated by an analysis of 187 reviews posted on, suggesting that popular representation of science fuels cynicism in popular and academic forums.

33 citations

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