# Celestial navigation guides

Short, plain answers to the questions people ask first. Each one leads into the lessons that teach it.

- [**Celestial navigation for beginners**How a sextant angle becomes a position, what you need, and where to start.](https://asterodos.com/celestial-navigation-for-beginners)
- [**How to use a sextant**Taking a sight: index error, bringing the body down, rocking, timing, correcting.](https://asterodos.com/how-to-use-a-sextant)
- [**The intercept method**Marcq St. Hilaire in plain words: Ho, Hc, toward or away, and the line of position.](https://asterodos.com/intercept-method)
- [**Pub. 249 vs Pub. 229**What each table covers, how precise it is, and which to carry.](https://asterodos.com/pub-249-vs-pub-229)
- [**How accurate is celestial navigation?**What to expect from a small boat, where the errors come from, and how to shrink them.](https://asterodos.com/how-accurate-is-celestial-navigation)
- [**How to learn celestial navigation**Online or from books: what works, and what to practice.](https://asterodos.com/how-to-learn-celestial-navigation)
- [**Glossary**Every term, with the lesson that teaches it.](https://asterodos.com/glossary)

## Free tools

- [**Noon sight calculator**The time of local noon, and your latitude from the Sun's noon altitude.](https://asterodos.com/noon-sight-calculator)
- [**Sun almanac**The Sun's GHA and declination for every hour of any date, 2026 to 2028.](https://asterodos.com/sun-almanac)
- [**Polaris latitude calculator**Latitude from the Pole Star, with the a0, a1 and a2 corrections.](https://asterodos.com/polaris-latitude-calculator)
- [**Star finder (2102-D)**A working 2102-D: the altitude and bearing of every navigational star at twilight.](https://asterodos.com/star-finder)

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From Asterodos, a free interactive course in celestial navigation: https://asterodos.com/guides
For learning, not for navigating a vessel.