# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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From: John Huth
Date: 2010 Jul 10, 03:46 -0400
I've tried a somewhat different approach.   Part of this was based on descriptions of how Polynesians were taught navigation and David Burch's book Emergency navigation as a jumping off point.   There were put into a hut with stars painted on the ceiling and had to memorize them.

I developed a system for memorizing the declination and RA for about 25 major stars, and had the students chart these, along with the ecliptic, and give their positions to a precision of a degree.   Obviously a 60 nm error is pretty horrendous, but still, you no longer need a star finder.

I then stole David Burch's technique for memorizing the equation of time, and developed my own technique for figuring solar declination as a function of day.   It starts with a sinusoidal approximation and then uses a memorization trick to get the last bits of accuracy out.  Using this, I can get a precision of about 10 arc-minutes of declination and equally good precision with the memorization trick for the EoT.

So, at the end of the course, they're able to identify stars without any aids, and get their location to a precision of a degree.   They can do somewhat better with the sun.

Rather than doing St. Hilaire, we use a watch where the rising and setting observations are good for longitude, and then use the meridian passage for latitude.   All of this is good for a precision of about 20 arc-minutes, I've found, without even using a sextant, but stuff we build from scrap.

We're all free to try our own approaches given the electronic age we live in, but I wanted to try to get the students as close to the nuts-and-bolts of what's happening in the sky that doesn't require any artificial aids, including tables.   This seems to have reached the students, who apparently retain this.   But, this is based on two years experience.

It's part of a broader course where they learn a lot of science (tides, currents - the Ekman spiral, weather, aerodynamics, hydrodynamics, dead reckoning, vectors, forces, energy, electromagnetic waves, how the brain creates mental maps, some geology), so it's not exclusively limited to celestial

John H.

On Fri, Jul 9, 2010 at 9:38 PM, Byron Franklin wrote:

I aggree with you, thats why I talk of "keep it simple.
Many have tried to keep Celestial Navigation in the main stream, of the seaman.
Why has it been a losting battle? I learned it, and have taught thousands. First the instructor has to be interesting, the course must have interest, the sea stories must be real and interesting and the class must be interested. Not a thing else counts. Also why don't the Astromony use the (Rude) star finder for finding stars? I try to change that with my two minute star finder. I made the finder to teach the sight form! down, the road will tell. I found that most Offiers that had class room training were reluctant to do a days work in Navigation, I had to chase most of them down, but my quartermaster jumped to it and learn quickly.WHY? The instructor should known theory but, use the sea storys to get apoint across.

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