Entry & progression
Governing: MSN 1858 (M) Amendment 2, sections 3.5, 3.6 and 7.4-7.5; MCA Celestial Navigation Examination Syllabus.
Every yacht master has been asked the same question by a guest: "Why bother, when there are three GPS receivers on the bridge?" The honest answer is that the regulator still asks for it, and that the day you need it you will not have time to learn it. This course teaches the method properly, with one passage worked all the way through.
Where celestial sits in the yacht route
| Certificate | Celestial requirement | Source |
|---|---|---|
| Master Code Vessels <200 GT unlimited, Chief Mate (Yachts) <3000 GT | RYA Yachtmaster Ocean certificate plus shore-based Ocean course (or IYT Master of Yachts Unlimited) | MSN 1858 A2, 3.2 and 3.4 |
| Master (Yachts) <500 GT | Pass the MCA 'Celestial Navigation' professional examination | MSN 1858 A2, 3.5 |
| Master (Yachts) <3000 GT | Hold the <500 GT CoC, or all module passes with Celestial Navigation less than 1 year old at issue | MSN 1858 A2, 3.6 |
Two rules catch people out. First, there is no set module for celestial: you may self-study and sit the exam (7.4). Second, the pass is valid for 1 year, against 3 years for the other modules (7.5). Time it close to your oral.
The MCA paper
The MCA syllabus sets a written 2.5-hour paper of four questions. The pass mark is 65% overall, and you must also score at least 65% in question 1. The aim is that you can fix the ship's position and find compass error from celestial observations at the level needed for an ocean passage worldwide. The syllabus covers:
- compass error by azimuth (sun, star or planet) and by amplitude of the sun;
- selecting stars for twilight, and times of sunrise, sunset and twilight;
- sight reduction by calculation or tables to find intercept and true bearing, and plotting the fix;
- a transferred position line crossed with a meridian altitude;
- latitude by the sun's meridian altitude and by Polaris.
Use, care and errors of the sextant are examined at your oral, so Module 2 matters as much as the arithmetic.
The Yachtmaster Ocean
The RYA exam is oral and written, about 1.5 to 2 hours. You must bring your own ocean navigation: a planned, reduced and plotted sun-run-meridian altitude or sun-run-sun, and a compass check by bearing of the sun, moon, a star or planet, sent to the examiner 48 hours before. The qualifying passage is at least 600 miles, including 200 miles more than 50 miles from land, lasting at least 96 hours. Passing the shore-based course's invigilated exam exempts you from the written part. The shore-based course itself is at least 40 hours plus exam time.
Our worked passage
Every example in this course uses one passage, computed and cross-checked:
| Item | Value |
|---|---|
| Vessel | Motor yacht, Las Palmas towards Antigua |
| Date | 25 November 2026 |
| Course / speed | 262°T at 11.0 knots |
| Height of eye | 3.2 m (bridge wing) |
| Index error | 1.8' on the arc |
| Ship's time | Zone +2 |
CAUTION — Illustrative almanac values The 2026 almanac figures in this course were computed from an ephemeris, not copied from the printed Nautical Almanac. They agree to about 0.1' but are for learning only.
Cross-refer to Yachtmaster Ocean for passage planning and ocean meteorology, which this course does not repeat.