Course Objective: Prepare sailors to skipper a vessel in all oceans anywhere in the world by day and by night and be able to navigate only by means of celestial navigation
Pre Course Experience: Yachtmaster Offshore license or equivalent
Assume Knowledge: 3000NM at sea with some night experienceand a good command of a sail boat. VHF license. Medical Test and preferably STCW95
Duration: 6 days theory, 6 days at sea
Cost: contact us
What will I learn?
- History of astronomy and celestial navigation
- Principle of astronomy
- Circle of position
- Spherical trigonometry
- Sight taking
- How to read an almanac
- Sight reduction techniques (Sumner and St Hilaire)
- Latitude by Polaris
- Noon sighting and Sun Run Sun
- Understanding time
- Star identification and sight planning
- Passage planning with sights
This is a course for anyone serious about sailing. Celestial navigation is an important skill and is still taught today even though GPS have become so convenient and affordable. Even though the GPS system (and other similar services) are reliable, we are still at the mercy of solar flares which can disrupt permanently any satellites (as it nearly happen, by 1 week in 2012 according to NASA) and/or lightning strikes which will disable any electronic equipment on board.
At the beginning of this course, we will take a trip back in time and start our journey of the stars with the first greek astronomers. We will pay respect to Eratosthenes and Aristarchus for their brilliant intuition and mathematical genius in discovering that our planet is a sphere and not at the center of the universe, more than 2000 years before Galileo and Copernicus. We will explore the first methods for finding a position using stars and how celestial objects locations in the celestial sphere were recorded in almanacs. On the way to modern times, we will salute Sumner and St Hilaire for giving us, back in the mid 19th century, the 2 main methods used for sight reductions today.
For those of you who have not done any spherical trigonometry since high school, don’t worry, we go back to the basics and re-explain the sine and cosine laws for planes and spheres (high school 10th grade). These laws are used throughout the course and it is important to understand how they are useful to calculate the length in degrees between 2 points or to calculate an angle (to compute an azimuth for instance or a longitude).
Our school has several sextants for students, from simple Mark 3 sextants to the very powerful and precise Astra III and Tamaya They will be used for noon/sun sighting during the day and star altitude observation at night.
We will then explain how to read an almanac to extract the Geographic Position of the observed celestial object, do all our fine tuning by including all the necessary corrections like dip, altitude, sextant errors …
From the almanac readings we will have a correct GP of celestial objects which will then be used with either pure trigonometry or using sight reduction techniques (a semi-graphical method) to obtain our position. Et voila !
Before finishing, we will look at “time” and awe at its complexity. We will learn about Aphelion, Perihelion, Analemma, Equinox, Solstices, the path of the Earth around the sun, the difference between apparent solar time (used by ancient Greeks with their gnomon), mean solar time (used by you and me with a watch) and sidereal time (used by astronomers). And you will finally understand why we constantly need to adjust our watches because a day is not really 24 hours !
With this certificate, you can charter a boat anywhere in the world and skipper a boat day and night up anywhere you want. So buy a sextant, practice and take it with you on your boat!
It’s recommended that you contact us to book your IYT – Yachtmaster Ocean.
Call +886 918996671 (please, remember the time difference with Taiwan : UTC/GMT +8 hours) to inquire or book or use our contact form.
All our courses are conducted based on the criteria of: IYT – International Yacht Training
IYT – Yachtmaster Ocean Course price:
You can pay by cash or Paypal. All our prices are fixed.
Our course package includes: boat rental and IYT instructive materials, instructor’s fee, warm lunch made from fresh local ingredients (when on the boat).
Note: All our courses have to be paid in Taiwan Dollars. The prices in US$ are informative.