Celestial Navigation: A Practical Guide to Knowing Where You Are
by David Berson
This short book — only 133 pages — delivers just enough information for the reasonably competent coastal navigator to become a reasonably competent celestial navigator. Berson’s folksy writing style, which readers of these pages have come to appreciate over the past two decades from his regular Nav Problem and from his seminars with the Ocean Navigator School of Seamanship, renders the material not only understandable but enjoyable as well. In fact, I recently read the book from cover to cover on a flight, pausing only long enough to look out the window at the horizon or the blue dome of sky to contemplate the angles, as if comparing my own position in lat/long relative to the sun’s geographic position in declination and Greenwich Hour Angle (GHA). I could literally see the Local Hour Angle (LHA) because of Berson’s vivid descriptions and accompanying diagrams.
Berson acknowledges the many mathematical wizards in nautical history who have made such a straightforward book possible, from Bowditch to Mixter, but he is also humble enough to acknowledge you don’t need more than addition and subtraction skills to be proficient in celestial; you just need practice and a willingness to engage in and appreciate the magic. His approach mirrors his teaching style: He explains a concept — how to utilize dead reckoning to derive an assumed position or calculate LHA, for example — and then, after adding another basic step, loops back to scoop up the previous two or three concepts in a form of perpetual review. One small step forward, a few steps back, another small step forward. The cumulative effect, of course, instills the reader in the three dimensions necessary for visualizing how it all fits together. He’s a canny enough teacher to provide cheat sheets, which show the novice how to perform each of the steps in order, and which will bring the novice along until the big picture becomes crystalized in the mind through practice.
There have been other books on the subject over the years, but none as concise and accessible. Berson’s joy at describing his own pleasure in the craft (and art) of engaging in celestial navigation will carry even the clumsiest navigator to the satisfaction of finding one’s way with the sun and stars.