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

Published online by Cambridge University Press:  18 January 2010

E. W. Anderson  and
D. H. Sadler
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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
Information
The Journal of Navigation , Volume 6 , Issue 4 , October 1953 , pp. 333 - 357
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 1939–1942.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
3Weems, P. V. H.Star Altitude Curves. Weems System of Navigation, Annapolis, Md. First edition 1928; second edition 1938; third edition 1940.Google Scholar
4 Personal communication.Google Scholar
5Wimperis, H. E. (1920). A primer of Air Navigation, Constable & Co. Ltd., London; p. 104. This book contains what is possibly the first description and example (p. 81) of ‘Two-star altitude tables’, giving latitude and L.H.A. Aries with the two altitudes as arguments.Google Scholar
6Beij, K. Hilding (1924). Technical Report No. 198. Astronomical methods in aerial navigation, in the Tenth Annual Report of the National Advisory Committee for Aeronautics, Washington; pp. 269—320.Google Scholar
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
7U.S. Hydrographic Office. Tables of Computed Altitude and Azimuth, Hydrographic Office Publication No. 214, Washington, D.C., Vols. I to IX. First edition (Vol. IV) 1936; other volumes and editions in later years.Google Scholar
8Japanese Hydrographic Office. ‘Celestial Air Navigation Tables’, seven volumes covering latitudes 0° to 70°. Japanese Hydrographic Office Publication No. 351. Tokyo 1940 and later years. These tables were originally issued under a ‘Secret’ classification and appear to be the same as the later (unclassified) publication No. 603. Only the star names are given in English; everything else (other than figures) is in Japanese. See the review by C. H. Smiley in Mathematical Tables and Other Aids to Computation, Vol. II, p. 44, 1946.Google Scholar
9Hutchings, Lieut. C. H., U.S.N. (1942). Tables of computed star altitudes and true azimuths. Proc. U.S. nav. Inst., 68, 1279. In the same volume there are comments on this paper by Commander Arthur A. Ageton, U.S.N. (p. 1303), and by Lieut. Commander P. V. H. Weems, U.S.N. (Rtd.) (p. 1760).Google Scholar
10U.S. Hydrographic Office. Star Tables for Air Navigation, Hydrographic Office Publication No. 249, Washington, D.C. Preliminary edition 1947. A definitive edition, three volumes, has been published under the revised title Sight Reduction Tables for Air Navigation (Vol. I (Star Tables) 1951; Vols. II and III (Declination Tables) 1952).Google Scholar
11Sadler, D. H. (1948). Review of preliminary edition of H.O. 249. This Journal, 1, 97Google Scholar
12Hoehne, G. C. (1943). Practical Celestial Air Navigation Tables, Vol. II. The Navigation Publishing Co., Miami.Google Scholar
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
14Deutsche Seewarte (1940 and later years). Ortsbestimmung durch astronomische Beobachtung zweier gegebener Fixsterne mit Hilfe van Höhengleichendiagrammen, Issued by Oberkommando der Kriegsmarine.Google Scholar
These are very similar in concept and execution to Weems's Star Altitude Curves.Google Scholar
15Ménéclier, Victor, and Chevalier, Roberto (1945). Calculo del Punto por altures de estrellas, Tomo 4 (años 1940 a 1960, latitudes de 30° a 39° sud), Republic Argentina, Secretariá de Aeronáutica (Reservado), Buenos Aires, 1945.Google Scholar
16Sadler, D. H. (1948). The provision for astronomical navigation at sea. This Journal I, 306. Detailed proposals for ‘star tables for surface navigation’ were circulated in stencil form early in 1948.Google Scholar
17A.P. 3270, Sight Reduction Tablesfor Air Navigation, H.M. Stationery Office, London. Vol. 1 (Selected Stars) 1952; Vols. 2 and 3 (Declination Tables) in press. These tables constitute the British edition of H.O. 249 (Ref. 10), with which they are essentially identical.Google Scholar
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
19Ashton, Philip (1952). Astrograph-time star tables for air navigation. This Journal, 5, 377Google Scholar
20A report on the ‘Longley Star Computor’ was produced by the Central Navigation School in November, 1945.Google Scholar
21Jessell, A. H. (1948). A precession table for correcting astro fixes. This Journal, 1, 268.Google Scholar
22Sadler, D. H. (1952). The correction of astro fixes for precession. This Journal, 5, 375Google Scholar
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