Line Of Position Navigation:: Sumner And Saint-Hilaire: The Two Pillars Of Modern Celestial Navigation
Co-author Michel Vanvarenbergh learned the basics of navigation at an early age from his father, a merchant marine captain and maritime pilot.  He was an engineer before becoming a commercial airline pilot for Sabena World Airlines, qualified as Captain and flight instructor.  He taught aircraft navigation at the national Belgian Ecole d'Aviation Civile and wrote the course that is still in use there.  Celestial navigation, and particularly the study of historic techniques, has been an area of special interest for more than 30 years. Co-author Peter Ifland is a retired Commander in the U. S. Navy Reserve, having served as a deck officer on destroyer types in WWII and Korea. Ifland holds a Ph.D. in chemistry and spent his professional career as a manager in R&D; for a multinational consumer products company. He has a special interest in the hand-held instruments used for celestial navigation. He has also written "Taking the Stars: Celestial Navigation from Argonauts to Astronauts," and published numerous articles on celestial navigation instruments.