If you want a book that will not only help you to pass exams but also teach you to navigate and to understand what you are doing, then you have come to the right place. This unique course comprehensively covers all elements of the examination syllabi of the main sailing associations. The traditional 'formula method' of celestial navigation which involves the use of trigonometry to calculate a vessel's position is comprehensively taught in this book. With this method, we make accurate calculations using data taken directly from the DR position and so avoid the inaccuracies of sight reduction methods that involve interpolation from tables using data based on an 'assumed position' which is usually some distance from the DR position. Although the prime aim of the course is to teach the practical skills of celestial navigation, it is emphasised that without knowledge, skill is nothing. At the same time, it is recognized that students quickly lose interest if they are expected to plough through reams of theory before they can get down to the business of learning the skills. With this in mind, this course has been uniquely designed to teach the important skills from the outset while 'tying-in' the relevant theory as progress is made. There are numerous examples and test exercises that enhance the learning process and help to embed the knowledge and skills needed to practice the art of celestial navigation.