Previously "Ocean Yacht Navigator", this book has been revised by Langley-Price and Ouvry from Wilkes's original. It explains how to work out sight reductions for the sun, the moon, the four navigable planets, the 57 selected stars and Polaris. It also covers: the RYA Ocean Yachtmaster syllabus; the use of the sextant; taking sights in heavy weather; planning an ocean voyage; hyperbolic and satellite navigation and the use of navigational calculators; and graded exercises with detailed model answers.