Astro Navigation Remembered

Abstract

The authors give a personal account of the use of astro navigation during the years before GPS became the primary aid for oceanic navigation. The paper also contains an account of the support provided by The Nautical Almanac (NA) together with its associated tables and computer programs which ease the tedium of sight reduction while leaving the satisfaction to be found in successful astro observations at sea.An early version of Section 2 of this paper formed part of a presentation made at the Symposium After Longitude – Modern Navigation in Context which took place at the UK National Maritime Museum from 22–23 March 2012.

Astronomical position without observed altitude of the celestial body

“…For comparison, the intercept method errors, arising from all causes, in an astronomical position line, in good conditions, are expected to range between 2 to 3 NM, depending on the skills and experience of the observer (Malkin, 2014). Top navigators can reach a precision within 0·4 NM from the GPS position, under calm sea conditions (Hohenkerk et al, 2012).…”