Celestial Navigation for Sailors with Tom Tursi

By: Books

Celestial Navigation seems to be something that only the old salts talk about as necessary. Why do we need to seek out the sun and the stars to helps us navigate? These days with GPS systems on our mobile devices we feel as if we can find our way with ease. Well, navigation has become more convenient; but what would you do if your electronics failed?

Celestial Navigation is not at all complicated considering all you need is the sun, a watch, a sextant, and a nautical almanac. Get a reading at noon of your location using the sun, a  watch to note the time, and a sextant. You’ll need a nautical almanac to get some more information, and you’ll be able to plot your location on your chart. 

Easy, right?

ASA asked Author and Sailing instructor, Tom Tursi of The Maryland School of Sailing & Seamanship to tell us about his book, Celestial Navigation for Sailors, and the importance of Celestial Navigation.

Celestial Navigation in this Age of Super Electronics

I am often asked the question: “Why are you still doing celestial navigation when you could just punch a few GPS buttons and have your answer? Presto!” One answer to that question is “In case the GPS fails.” But the real answer goes a lot deeper than that, something along the lines of “Why are we sailing this slow boat to Bermuda when we could fly commercially faster, cheaper, safer…”

We could fly, but we chose to sail. And why did we do that? Well, there are many answers to this question, but having sailed offshore with many different sailors for the past 30 years, I think the answer for most lies in the desire to escape from the high-octane world in which we live and work today. Get back to some basics. Use your hands to do things and your brains and good judgment to unravel mysteries. Overcome challenges. Marvel at the open sea. Meet a storm on terms dictated by Mother Nature.

It’s uncomfortable and intimidating at sea a lot of the time, but what a fantastic experience; what challenges; what memories! Sailing day and night, day after day, an entire week! Porpoise, whales, flying fish, Portuguese men of war, tuna, shark, Bermuda longtails… Beautiful sunsets, billions of stars, storm clouds, lightning, howling winds, brilliant sun, ponderous waves… Navigational challenges, passing ship lights, fishing trawlers, weather forecasts, distant radio emergencies, sonic booms… The Gulf Stream, uninterrupted sailing, miles deep, Sargasso weed, tropical waves, deepening low… Rhumb line, magnetic variation, landfall, rage sea, peace at last…

Celestial navigation at sea is an integral part of this experience. Back to basics. Pull it out from deep within. Remember your youngster days of learning something new and difficult and marveling that it actually works when given the time and patience to delve into details? A simple optical telescope, a clock and some reference tables. Focus on a star at the outer limits of the universe billions of light-years away; capture its now dim light and measure its angle above the earth’s horizon. From this, you determine your position on this seemingly endless sea using the methods of our forebears. 

ASA Offers Two Courses in Celestial Navigation:

ASA 107, Celestial Navigation
Learn the celestial navigation theory and practices for safe navigation of a sailing vessel in offshore waters. On-water celestial navigation skills elements are demonstrated in ASA 108, Offshore Passagemaking.

ASA 117, Basic Celestial Endorsement

Learn to apply basic celestial navigation theory and practice to determine latitude and longitude at sea using a sextant and Nautical Almanac.

ASA 107, Celestial Navigation

Celestial Navigation for Sailors, written by Captain Tom Tursi, a USCG Licensed Ocean Master with over 70,000 miles of blue water ocean sailing throughout the world in sailboats under 50 feet. This is a step-by-step instructional text, specifically directed at ocean sailors, covering the celestial theory, calculations and procedures needed for hands-on practical navigation at sea. It covers the Sun, Moon, Planets, Stars and the 2102D Star Finder in detail, plus the Log entries and Dead Reckoning (DR) procedures used to assemble the celestial lines of position (LOPs) into a useable ocean navigation process. It also includes sample calculations for all of the celestial bodies used for navigation, homework exercises and extracts from the Nautical Almanac and Sight Reduction Tables needed for these calculations.

Solutions to Celestial Navigation Questions is a companion book, also by Captain Tursi, showing detailed, step-by-step solutions to the homework exercises in Celestial Navigation for Sailors.

Interested in the Celestial Navigation book? Buy it from the Maryland School of Seamanship. These books are priced at $50 retail for the two-book set.