The Use of ABC Tables in Preparing for Star Observations

Extract

As part of their navigational outfit many of the ships in service today are equipped with Sight Reduction Tables (A.P. 3270 = H.O. 249), and many navigating officers include amongst their personal kit a Rude Star Identifier (H.O. 2102), or some similar device according to individual preference, for the purpose of obtaining the approximate altitude and azimuth of a selected body as a preliminary to making observations, particularly for star sights. However, for the benefit of those without such means at their disposal and as a matter of interest for others, the use of ABC tables for this purpose is suggested. The origin and author of this method are not known and it does not appear to be included in any of the navigational manuals which have been in circulation in recent years, but there was reference to it by Capt. S. T. Lecky in his General Utility Tables first published in 1897, a reference for which I am indebted to Capt. C. H. Cotter.