A short course that teaches the basic celestial navigation you need to find your way across an ocean, as a reliable backup to GPS.
Ocean sailors are prudent: they carry a backup for every critical system. Celestial navigation is the answer to losing GPS for any reason. But not every sailor wants to learn cel nav at the depth our parents and grandparents needed. GPS is here, and it's reliable, but it isn't infallible.
This course is a fast way to gain the knowledge you need to keep cel nav as a backup, so losing your standard navigation aids won't leave you stranded. It covers the basic celestial navigation needed to reach safety across any ocean, with nothing more than a small book, a watch and a sextant. The sextant can be the most basic plastic model or any other of your choice. The books teach you to take sextant sights on your own with any sextant you have, and the instructors can help check your sights during the course.
COURSE LESSONS
1. The sextant and basic concepts
2. Timekeeping and latitude from the sun at noon
3. Longitude at meridian passage
4. Latitude from Polaris
5. Universal plotting sheets and dead reckoning
6. A day at sea with backup cel nav: putting it all together
COURSE MATERIALS
• GPS Backup with a Mark 3 Sextant by David Burch: all instructions and tables included, for any ocean on any date (a short book with 35 pages of text and 65 pages of tables designed to make finding latitude and longitude fast and easy)
• How to Use Plastic Sextants
Prerequisites: None. The few topics covered are quick and easy to master.
Time required: 15 to 30 hours, depending on how much optional material, how many exercises and how much help with practice sights you choose.
Personal sight analysis: If your results are outside the specified uncertainties, you can send your sextant sight data to the instructors for analysis. The beauty of cel nav is its transparency: when results are clearly wrong, the reason can almost always be found from a series of sights.