This is the shortest book on celestial navigation we know of. Even so, nothing essential is left out. There have always been two widely divergent approaches to teaching celestial: provide a long list of rules for making computations and plots; or explain the theory and mathematics so that the reader gains a thorough understanding, and can invent as he goes. This book strikes the perfect balance between the two by explaining theory in an uncomplicated way, and omitting unnecessary detail. With excellent pictures and diagrams, this book is one of the best intermediate starting books available, and is certainly the best refresher to be had. We also have frequently recommended this book as a "second" book, where a different approach is desired.Uses HO-249. SC,2001, 64 pages SW 0.5 lbs