Navigational Almanacs for small Computers and Calculators

Abstract

In 1947 Dr G. M. Clemence, then Director of the Nautical Almanac Office at the US Naval Observatory, and I visited a number of US institutions engaged in the development of digital computing machines, with a view to their application to the calculation of astronomical ephemerides. We were, at that time, planning the revision of the almanacs for surface navigation which led, in due course, to the unification of The American Nautical Almanac and The Nautical Almanac, Abridged for the Use of Seamen in essentially its present form as (from 1960 onwards) The Nautical Almanac. We were told (actually by an astronomer, Dr T. E. Sterne) that our efforts were pointless since, in the near future, a navigator would be able to calculate the astronomical data that he required to reduce his observations by digital computer; conventional almanacs would no longer be needed. Thirty years later that optimistic forecast, although not yet realized, requires consideration. However, no one could have foreseen that the microprocessor of today is far more powerful than the most elaborate computer that was then practically visualized. For that matter, few would have thought that there would still have been a demand for astronomical data for navigation; the basic principles of many other aids to navigation were rapidly being developed.