For reducing the Moon's Declination, as given in the Nautical Almanac for Noon and Midnight at Greenwich, to any other Time under that Meridian; or to Noon or Midnight under any other Meridian

Author(s):  
Nevil Maskelyne
Keyword(s):  
Nature ◽  
1891 ◽  
Vol 44 (1147) ◽  
pp. 593-593 ◽  
Keyword(s):  

1968 ◽  
Vol 21 (1) ◽  
pp. 6-18 ◽  
Author(s):  
D. H. Sadler

In ‘A Modern View of Lunar Distances’ (Journal, 19, 131) H.M. Nautical Almanac Office has already covered most of the technical aspects of the method of lunar distances which the Almanac made practicable; in ‘The Foundation and Early Development of the Nautical Almanac’ (Journal, 18, 391), Dr. E. G. Forbes has given a scholarly, fully documented, account of the early history of the Almanac; and Mr. Sadler himself has written many articles on various aspects of the bicentenary. This general account, which necessarily must duplicate parts of these articles, is directed as far as practicable to those aspects that are likely to be of greatest interest to members of the Institute not technically concerned with astronomical navigation. The paper was presented, in an abridged version, at the Annual General Meeting on 25 October 1967.


1950 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Harold Spencer Jones

The Institute has now completed two years of its existence. The papers which have been read before it during these two years have covered a wide range of subjects and have served to emphasize the many ramifications of the science of navigation. Because of the high speed of modern aircraft, air navigation presents more problems and of greater variety than surface navigation, but even on the problems of surface navigation there has been ample scope for a wide range of discussion. The Institute has taken a prominent part in the discussion of the proposals for the revision of the Abridged Nautical Almanac. It might with some reason have been supposed that there was nothing more to be said on the methods of reducing astro-sights and determining position at sea. The problem is perfectly straightforward and there is a limit to the number of different ways in which the spherical triangle can be solved. But the essential basic data can be presented in a variety of ways, while there are many possible methods of presenting tables for the solution of the spherical triangle. The decision to use Greenwich hour angle instead of right ascension in the Abridged Nautical Almanac has followed its adoption in the Air Almanac; the revised Almanac will have an entirely different format from the present, while the methods of reducing sights must be correspondingly modified.


1932 ◽  
Vol 1 (1) ◽  
pp. 18-25

Albert Abraham Michelson was born on December 19, 1852, at Strelno in Posen, now restored to Poland. When he was two years old, he was taken by his parents, Samuel Michelson and Rosalie (Przlubska), to the United States, and, after some fifteen years spent in Virgina City, Nevada, where his brother Charles was born, San Francisco became their home. There his sister Miriam, the author, was born, and the boy attended the high school. He was given, in unusual circumstances, an appointment in the U.S. Naval Academy at Annapolis, and after graduating in 1873 he became a midshipman in the U.S. Navy for two years and was afterwards appointed instructor in physics and chemistry in the Naval Academy in 1875, holding the appointment until 1879. His next year was spent in the Nautical Almanac Office in Washington, and then he studied for two years at the College of France, and at Heidelberg and Berlin. In 1882 he became Professor of Physics in the Case School of Applied Science at Cleveland, Ohio. After seven years he went as Professor of Physics to Clark University, Worcester, Mass., and remained there until 1892. He was then appointed Professor at the head of the Ryerson Physical Laboratory, Chicago ; this appointment he held until shortly before his death, which occurred on May 9, 1931. He married Miss Edna Stanton of Lake Forest, Illinois, in 1899, and they had a son and two daughters. This in brief contains the history of his official appointments : how he filled the various posts is another matter.


It was with great pleasure that I received the invitation from the Director, Mr Greenhill, to open the Cook Gallery in the National Maritime Museum. For Cook had long been one of my heroes, as one of the greatest navigators and explorers of history. In addition, he was, in Fanny Burney’s words, ‘. . . the most moderate, humane and gentle circumnavigator who ever went upon discoveries’. Cook’s first voyage, which started at Plymouth in August 1768 and which we celebrate today, 200 years later, occurred at a turning point of the technique of navigation. His navigation on his three years’ voyage depended for longitude on the measurement of the angular distance of the moon from the fixed stars. It could take up to four hours of numerical calculation to work out the longitude. Cook had clearly trained himself to be a first-rate observer and an accurate calculator. This method of lunar distance became of practical use at sea only when the essential astronomical data became easily available to seamen. This happened in 1767, the year before his voyage, because of the publication of the Nautical Almanac and Astronomical Ephemeris by the Astronomer Royal. By this method Cook was generally able to determine the longitude to less than 30 miles.


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