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The Genesis of the E.A.N.T.s

Published online by Cambridge University Press:  18 January 2010

Extract

During 1943 there was produced, for trial purposes, a limited edition of the so-called Experimental Astronomical Navigation Tables (E.A.N.T.s). For various reasons these tables were not adopted for general service use in the Royal Air Force, and copies are no longer available. The tables possess some points of interest, which are described below for the first time.

Type
Research Article
Copyright
Copyright © The Royal Institute of Navigation 1953

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References

REFERENCES

1H.M. Nautical Almanac Office. Astronomical Navigation Tables, Volumes A to Q. H.M. Stationery Office, London 19391942.Google Scholar
2Baker, T. Y., and Filon, L. N. G. (1920). Position fixing in aircraft during long distance flights over the sea. Trans. R. Aero. Soc. G.B. 2. This pioneering paper contains much material of interest and will repay study even thirty-four years after it was written.Google Scholar
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On page 302 the author describes what are essentially star altitude curves, under the name ‘Two star diagram’, with a footnote ‘Proposed by the author’. Yet two pages later (p. 304) he describes the Baker navigating machine which uses an identical principle for the stars (actually three stars were used), with the added superposition on to the actual chart. This report is most competently produced and deserves to be better known in this country.Google Scholar
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13Höhentafeln nach Sternzeit, herausgegehen vom Technischen Amt des Reichsluftfahrtministeriums, Berlin, 1944. These tables give altitudes and azimuths of six stars for each even degree of latitude and every minute of sidereal time.Google Scholar
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These are very similar in concept and execution to Weems's Star Altitude Curves.Google Scholar
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18A specimen section of the Anderson ‘Astro-Scales’ was printed for trial purposes as special chart D. 6478 by Hydrographic Department, Admiralty, in June 1945. They give, on a scale of 13 inches to one hour of mean time, graduated non-linear scales for five stars and the Q-correction; azimuths and bearings are overprinted in red at appropriate intervals. A few copies are still available in H.M. Nautical Almanac Office.Google Scholar
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20A report on the ‘Longley Star Computor’ was produced by the Central Navigation School in November, 1945.Google Scholar
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23Sadler, D. H. (1953). An Improved Astrograph. This Journal, 6, 373. These suggestions were previously circulated in typescript at the end of 1952.CrossRefGoogle Scholar