A COMPANION TO THE AZIMUTH TABLES. By H. B. Goodwin, M.A., F.R.A.S., formerly Examiner in Navigation and Nautical Astronomy under His Britannic Majesty’s Board of Education. Glasgow: James Brown and Son, Nautical Publishers, 1925.
Reviewed by G. W. Littlehales, Hydrographic Engineer
The reputation of Professor Goodwin as the leading author in pointing the way to improvements in the applications of astronomy to the practice of navigation in the present generation is fully sustained in this excellent work, the contents of which are worthy of the fine execution which makes its issue a credit to the nautical publishing house of James Brown and Son, of Glasgow. A master of clear and pleasing presentation, drawing upon the rich accumulations of a career devoted to improving the insight of navigators into those applications of science without which no cargo is ever exported or brought home across the sea, here brings to the understanding of seafarers a knowledge of the varied ways in which the tables that have been provided for their use may be made conveniently to subserve their requirements in the practice of navigation.
It is of great practical advantage to the navigator to learn to be recourceful in the use of equipment—to know, for instance, how the solar azimuth tables may serve to yield values of the azimuth of celestial bodies beyond ecliptic limits, and how the tabulated values of the azimuth may be employed to find the course to be steered in pursuing a great circle route in any latitude. Looking beyond the present great importance of the azimuth in finding the error of the compass and indicating the direction of the Sumner line of position, there are indications of the endeavor to employ the observed value of this element in combination with the observed altitude of the same celestial body in finding in a single operation both the latitude and longitude of the observer: Thus it is that ample justification exists for regarding as important the considerations which the author has introduced with reference to conditions favorable to each of the various methods of finding the azimuth.
His fructifying touch has not been reserved alone to the British azimuth tables, but has been bestowed also upon the altitude and hour angle tables of recent times to show the expedients, in the form of convenient interpolation tables, that may be employed for their more perfect use.
Those interests which take account of the necessities of aviation at sea from the fleet as a base will welcome the inclusion in this book of an exposition of the original manner in which astronomical position-finding in flight over the ocean was made to succeed by Rear Admiral Carlos Gago Coutinho and Commander Sacadura Cabral in the airplane voyage which these two Portuguese naval officers made from Lisbon to Rio de Janeiro in the spring of the year 1922.
Indeed, to take the time to read the one hundred or so pages of this book opens one of the most direct avenues toward becoming well read in the resources available in the practice of nautical astronomy.