The Sight Reduction Tables for Marine Navigation (Pub 229) is published in six volumes, each of which contains two-eight degree zones of latitude with a one-degree overlap between volumes. They are designed to facilitate the practice of celestial navigation at sea. The tables are primarily used with the intercept method of sight reduction by entering arguments of latitude, declination, and local hour angle and obtaining tabulated altitudes and azimuth angles. The tables are prepared and published by NIMA on an as-needed basis.

This 2019 edition of The American Practical Navigator (Bowditch), Pub No. 9, exists to codify the latest body of marine navigation knowledge and practical application. Its publication success is a result of the dedicated efforts of many hands and voices from academia, science and seafaring experts. This edition has advanced from the judiciously shaped recommendations-some comprehensive, some minute, all indispensable-of a multitude of maritime and science professionals. At the same time, it was equally essential that those recommendations be compared, vetted, and applied in a consistent manner and with a clear vision, a challenging task performed in exemplary fashion by this edition's principal editor, Dr. Gerard J. Clifford, Jr.

As in previous editions, the symbols used on paper nautical charts produced by NOAA and the NGA and digital raster representations of those charts, such as NOAA Raster Nautical Chart (NOAA RNC's), are presented in lettered sections organized in categories, such as Landmarks, Depths, and Lights.