Multiple Sun Sights with One Reduction

Abstract

The small-craft navigator is beset by a number of problems in taking sextant observations; of these wave motion is foremost for the constantly changing height of eye makes the dip correction uncertain. One alternative is to take a number of sights and average the times and altitudes; but averaging angles, and especially times, is an error-prone occupation and if one of the sights is badly in error it will probably not be noticed, and will bias the resulting average. This would be avoided if all the sights were individually reduced and plotted, but the work involved is prohibitive. The method here described permits several sights to be taken and the individual position lines plotted, but requires practically no increase in work over a single sight. Inspection of the position lines will give a very accurate average and also indicate immediately if one of the sights was in error either in recorded altitude or time.