A Great Celestial Navigation Course

Celestial navigation has the reputation of being complicated, obscure and, depending on your relation to mathematics, bordering black magic. Not really knowing much about the topic, I dived into the practical aspects of measuring one’s position through the observation of various celestial bodies.

I found the online course below to be incredibly useful, on point, and simple. The course is divided in two videos.

The first video lasts less than three hours and explains all the concepts through three dead simple diagrams. If you understand the diagrams, you understand why and how celestial navigation works.

I very much liked the professor’s attitude in explaining how the principles are simple and helpful. It greatly reduces the chances of errors if someone has a mental representation of the calculations being performed. All in all, the first video is a good hook and prepares you for the second.

The second video is more taxing. It lasts eight hours (!) and goes into the calculation details. Eight hours of calculations. One can understand why someone may be discouraged!

That being said, the professor goes into the calculations in depth. As the professor states at the end of the video, routine calculations are repetitive and usually take five minutes. Thus, the extra 7 hours and 55 minutes in the video are devoted to the explanation of each aspect. Math-wise, all that is required is addition, substraction, and basic knowledge of geometry.

I watched the second video in roughly five periods of two hours (the extra time helped me review some aspects of the video). It is quite easy to digest, but it is also clear fro the video that practice is important to master the technique. There are several steps in the calculations where errors can be introduced by inadvertance.

All in all, these videos are great to introduce you to the topic and guide you into the calculations.

Is It For Me?

Celestial navigation is for ocean cruisers. It is a necessity if you have no other way to establish a position. That is the case when there is nothing on the horizon, nor any functionnal GPS onboard. If you plan performing ocean crusing, it may be a good backup method to have in your backpocket. If you seek a license or a certification, then it is a requirement for most advanced classes. Depending on your relationship to physics and maths, it may also be fun!

Going Full Geek

If you understand Newton’s third law and the Runge-Kutta method, you may be interested in how celestial navigation tables are built. There are great ressources as to how to build a planet motion simulator (even some accounting for relativistic effects). Moving from a simulator to a nautical almanach then becomes a matter of setting the proper starting conditions and a proper projection using spherical trigonometry. If you are solely looking for the resulting tables, there is good news: a sailor already did it. The Nautical Almanach is being produced by the SkyAlmanach-Py3 Python program, thanks to Andrew Bauwer.

Now, all you need is a sextant, a sailboat and a vast ocean…