Summer Solstice, Cr-Wikipedia
In a previous article looking at navigational awareness when travelling I mentioned some basic information on the Sun rising in the East and setting in the West; this subject is so complex that any generalisation is very often technically incorrect. As we are almost at the Summer Solstice I thought a little information may be appropriate.
As travellers are we really interested? The answer is, probably more than we realise. Although we all navigate to some extent, modern technology has removed the need for a basic understanding of the subject and this can be life threatening in extreme circumstances. What follows is no more than a rough guide to what’s happening and how it may be of use.
As we all know the Earth ‘tilts’ from its perpendicular axis, first one way and then the other; this is how we get the seasons. The extent of this ‘tilt’ or Solar Declination to use the correct term is 23.45 degrees North and 23.45 degrees South. The Tropic of Cancer and the Tropic of Capricorn are 23.45 degrees North and 23.45 degrees South of the Equator respectively… Could this be a coincidence?
These two imaginary lines, or parallels of latitude are projected around the globe and show the geographical limit that the Sun will be directly overhead at midday local time on the summer solstice; on the Equator the Sun will be directly overhead at midday local time on the March and September equinoxes. In latitudes North of 23.45 degrees North and South of 23.45 degrees South the Sun will never be directly overhead at any time of the year; this information is extremely useful to navigators.
Day and night
Travellers will know that at the equator the days and nights are almost equal throughout the year and as we move either North or South the days and nights get longer or shorter depending on how far we go and what time of year it is. It is important to remember that if we take the period of observation as one year (365 days) everywhere on Earth gets an average of 12 hours of daylight and 12 hours of darkness. This cycle is fortunately very predictable and to the navigator extremely important.
Why?
G.P.S. navigational aids have without doubt transformed the world in many ways, vast improvements in safety being only one. The problem is that as the level of navigational technology has increased our understanding of basic navigation has decreased; this, as we so often see on the news is a recipe for disaster when the technology fails and the lack of a basic understanding results in a needless death. Many travellers grow into adventurers and as an adventurer this becomes much more important; for the lone adventurer it is essential. As the lone adventurer explores remote areas the reliance on technology must reduce in order to maintain safety.
Try it out!
Natural navigation is not quite as rough and ready as you may think, next time you are out with your map and compass try telling the time with your compass instead of your watch (you’ll need information from your map to do this)! You’ll find it quite accurate, then try finding the direction with your watch to orientate your map; get used to doing all the maths in your head not on a calculator, it’s easy when you get into it.
I often think that the more I learn the less I actually know; it’s difficult to think of a subject that fits the statement better than this one.
How can this be of use?
Learning more about solar navigation can be of immense use to the adventurer; not least in a ‘peace of mind’ role. All knowledge and associated skills bring self-confidence; this will be of great benefit in your everyday life and come over in your personality. From a more practical point of view let’s take a look at an extreme scenario.
You have boarded a long haul flight that crosses the Equator, you have fallen asleep shortly after take-off. The next thing you know is that the plane is floating on the water and you have to swim for it; you are washed up on a small island and are the only survivor. Where are you? Your position may not seem that important. Is it? Well, yes, but perhaps not for the reasons you may think. Your position is academic as you have no way of conveying this information off the island to aid in any rescue. The real use of knowing where you are is that it will give you an idea of:
- What weather to expect.
- What temperature to expect.
- What dangerous wildlife to expect.
- What food may be available.
- What water may be available.
- What shelter may be required.
So, how do we go about it using the Sun?
The first thing is to determine which hemisphere you are in. A stick in the ground will tell you this. Shadows travel clockwise in the Northern Hemisphere and counter clockwise in the Southern Hemisphere in. You can find your latitude by measuring the Suns angle from the vertical at midday (making any allowances for solar declination). Your longitude can be found by comparing the time that the Sun is highest in the sky with GMT. Remember, the sun moves at 15 degrees per hour. So with the aid of only a watch and what you can find, you can estimate quite accurately where you are and what to expect.
Of course this scenario is extremely unlikely and is only an example of what can be done and why. The measurement of angles can be done with natural bits and pieces that will be lying about. You can make a right angle by making a 3,4,5, triangle; it then becomes easy to split this into 45 degrees and again into 22.5 degrees and so on.
Peace and quiet
You will also find that an interest in solar navigation will assists in your search for peace and quiet. As you wander around looking at the Sun, and then your watch, then the compass, and then a little stick producing a shadow, and then back to the compass followed by a little scribble in your notepad topped off by a smug grin you will find that everyone tends to give you a wide berth for some reason… Yet another mystery!
