The natural Navigation: The Right Course, Naturally

On holiday I did try very hard not to think too much about navigation, but wherever I am I cannot resist checking that the sun is behaving itself appropriately considering my latitude and the season. At 7 degrees north, Phuket is in the northern hemisphere and the tropics and because the sun is now well south of the equator the short midday shadow is cast towards the north. Nearer June this same pencil would cast a shadow in the opposite direction at midday, to the south.

This photo was actually taken eleven minutes after local midday, which is logical since it was taken in the west of Phuket and Phuket itself is in the west of the country, about 2 degrees west of Bangkok. The sun will be at its highest point over Phuket about eight minutes after it has reached its highest point when viewed from Bangkok.

I watched the History Channel’s ‘Expedition: Africa’ last night, a retake on Stanley’s expedition to find Livingstone. It is quite enjoyable if a bit ‘light’, the interest certainly coming from the internal politics of the expedition team rather than the nature of the journey itself. One thing did strike me, one of their challenges is billed as ‘using only compasses and basic maps’, which could only be billed as a challenge in the age of satellite navigation. Even this seemed to rob the team of some of their awareness of their surroundings. Pasquale Scaturro, the navigator, takes a compass bearing and then navigates from ‘tree to tree’ despite numerous clues in the sky and ground to help him hold a course. To be fair Benedict Allen does point out that the river would give a line to follow, but Pasquale does not seem to want the river to get between…

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Tristan


I managed to rope in a friend at the end of an evening’s BBQ and together we plumb-bobbed Polaris, set out two posts and then strung a string between them. We checked with a compass and, despite the evening’s beers, we were actually almost spot on!

The next day we checked the shadow at 1.00 (12 noon GMT) and found this lined up on our string. Impressed or what!

Richard

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Hi Richard,

I can see I’m going to need to come up with some sort of merit/badge/star system just to complete the back to school experience!

A link that I will have mentioned on the day is here:

http://aa.usno.navy.mil/data/docs/AltAz.php

If you plug in your latitude and longitude, it will give you the altitude and azimuth of the sun (or moon) for a whole day by GMT. Due south is often very close to clock midday, but it can wander off it depending on your longitude and because of something called…

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In this photo you can see the dew that the sun has not yet burnt off. The shadow itself is mostly moving right to left in this picture, leaving the thin band of wet wood in the shade all the time. This thin band is a rough east-west line at all times of the year, but quite an accurate one at times like this, close to the spring and autumnal equinoxes.

The small patch of moisture that is in the sun reveals the direction that the shadow is shortening, a crude north-south line as we near the middle of the day.

A blog is not a blog without an occasional rant, so…

It strikes me that the world of navigation training has strayed a little off course. If you type “navigation courses” into Google you get nearly five and a half million results. I’d be prepared to wager that more than five million of these are associated with ‘traditional’ training. To my mind the majority of these are falling between two stools. They focus on using tools but not the best ones. The two ends of the spectrum are electronics and nature. Nobody, myself included, argues that natural methods are more accurate than electronics when it is working. Equally, nobody in their right mind would want to challenge someone holding a working GPS to a position-fixing competition using compass back-bearings. Where am I going with this?

Well, why do we concentrate the vast majority of our training and learning in the area that…

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