The Sun is a Compass — Tricks in Orienteering

 

The sun is a compass.

     It rises in the east and sets in the west. Halfway through the day it’s in the middle – south, if you live north of the equator. It seems odd to have to say this, because people have been using the sun and the stars for orientation for as long as they have been on this earth. But in this modern world we follow roads and use the GPS and simple things become forgotten.

   These fundamental facts – it rises in the east, sets in the west, and goes through south at noon – are a basis for figuring-out your heading. If you have a watch and can tell the time – and can see the sun! – you can estimate your heading very closely.

     Let’s go through a tiny bit of Grade 4 arithmetic – don’t get scared! It’s very easy! Keep reading! The sun appears to go around the earth once a day, that’s 360 degrees. We divide the day into 24 hours. Divide 360 by 24 and you get 15. Thus, to us the sun moves 15 degrees per hour. (The earth rotates 15 degrees per hour.) Remember that! The sun moves 15 degrees per hour.

     If the sun rises in the east, and sets in the west, then halfway through the day – noon – it’s in the south. So if you look at the sun at noon, you are looking exactly south. (There are small errors here which we’ll cover later, but for all intents and purposes, it’s south.) South is a heading of 180 degrees-true. (You can scrap variation/deviation in this exercise since we’re not dealing with anything magnetic at all.) So if it was noon and you wanted to walk or paddle south, all you’d have to do is move directly towards the sun.

     The odds are though, that you need to know a different heading. Well, no problem: as we said, the sun moves at 15 degrees per hour. That means at 11:00 the sun hasn’t quite got to South yet. It’s 15 degrees short, at 165 degrees. At 10:00 it is 2 hours from noon, or 150 degrees. After noon of course, it’s the same thing: at 13:00 the sun is 195 degrees. At 14:00 it’s 210 degrees. Plus-3 and minus-3 are the same thing: 135 and 225 degrees.

   So with some extremely simple arithmetic, we’ve established a number of cardinal points that we can walk to. But what if we want to go in a northerly direction? Answer, stand up straight and use your shadow! For example if you put your back to the sun at noon, your heading is north, 360 degrees. That’s where your shadow points. At 11:00 we already established that the sun was at 165 degrees. So your shadow sticks out the other way, the reciprocal, or 345 degrees. At 13:00 it’s the same idea, the sun is at 195 degrees, so your shadow is at 015 degrees.

    Thus for the 3 hours on either side of noon, we have a whole range of points through south or north that we can establish.

   But what if we want to go east or west? Again, simple! Answer: put the sun directly abeam you. At noon, if you turn so the sun is exactly to your right, you’re heading east. Similarly, to the left, you’re looking west. Again the sun moves 15 degrees per hour, so if you put the sun on your left side at 13:00, you’re heading west, 270 degrees, plus the 15 degrees it has moved since noon – 285 degrees. At 14:00, sun abeam you to the left, you’re heading 300 degrees. Sun abeam you to the right, you’re heading 120 degrees.

     Pretty fancy, right? For the 3 hours on either side of noon, we can easily identify a heading 45 degrees on either side of the 4 cardinal compass points. That’s the whole circle! Magic! You can leave the compass in your pocket and amaze and astound your friends! (That is, as long as the sun stays out!)

     But what if it works the other way? What if you look at a map and identify that you want to steer or walk a particular compass course?

     OK, let’s work out an example. Say you want to snowshoe through the bush on a heading of 030 degrees to find some hidden lake. The time is 11:00. A-ha! You know the sun is at 165 degrees. If you put your back to it, you’re heading would be 345 degrees. Hmmm, you need to point another 45 degrees right (345+15+30=030). Well, 45 degrees is half of 90 degrees – half of a right angle. Half of a right angle is not too hard to estimate. If you turn to the right and point half of a right angle away from your shadow, or the shadows of trees on the snow, you’re walking on a heading of 030 degrees. In other words, look at the direction of the shadows, visualize a line 90 degrees to the right of it, and split the difference. Walk that way. Leave your compass in your pack if you want to amaze your friends! (But make sure you’ve got one in your pocket or pack in case of clouds!)

     However, an hour later, at noon, the sun has moved 15 degrees to the right, so you have to adjust that much to the left to compensate. How do you estimate 15 degrees? Well, in time it becomes obvious. You get a good idea of how much heading change that it simply through familiarity. You look up and say, “Another 15 right would be… about… there!” and point at the new heading.

     There is a method of estimating this that’s fairly accurate. The principle is that you divide a right-angle into portions, visually, by eyeball. For example, stand straight up. Hold your right hand up to point directly abeam. That’s 90 degrees to your right. Now split the difference between that and straight ahead. Point at that – it’s 45 degrees to your right. Now look at the remainder between your hand and straight ahead. Split that into thirds, 3 equal portions. Each of those is 15 degrees.

    That’s the finesse trick – being able to estimate blocks of 15 degrees, one hour of apparent sun movement. Figure out the 45 point, divide that into 15 degree chunks, and proceed accordingly. It’s not hard, with a bit of familiarity.

 

     There are some errors in this system. The obvious one is Daylight Savings Time. (Spring ahead, fall back!) The above method is for Standard Time. For orienteering in the summer, take an hour off to get ST, then do the calculations!

     The next one is that some time zones are irregular, adjusted for social factors rather than geography. The above method is most accurate in the middle of a standard 15 degree time zone. If you are at one edge or the other of the time zone, or it’s an odd shape on the map, you may have to nudge your course one way or the other.

   The last error is that the further you are in time from noon, the less accurate the method is. I generally refer to the compass after about 16:00.

 

     So what’s the point of all this? Well, the answer is simply that if you use the sun as a compass, you are always aware of your direction of travel. It becomes second nature. By occasional look at a map, you end up keeping a mental picture of your travel – a mental “plot” of your progress. It grows on you. Sure you can use a compass, and for very accurate orienteering you should, but most people don’t pull one out every minute. In the meantime, when a general idea of direction is required, the sun is always there. In the Northern and Western Canada, the sun is quite often visible – there is less cloud cover than in the southern portions of the country.

     This technique is simply one more way to feel at home, and comfortable, in the Bush. In time, you find yourself using it at home, too, in cities or during casual walks. (WARNING! You’ll still get lost in shopping malls!)

 

  A GPS is a marvelous thing. Pure fabulous magic. Nothing beats it for instant accuracy. But no mechanical device is perfect. It can get shattered, drowned, burnt, lost – or even eaten, I suppose. Batteries can certainly fail.

     Where a GPS really shines is going upstream through a marsh, trying to avoid taking a tributary. It’s nearly impossible to get lost going downstream – everything converges – but going upstream everything diverges. All those twists and turns make you dizzy, and sometimes the tributaries are the same size as the main stream, and you can take the wrong one, and lose a half-day’s travel.

     It’s the same in a jumble of islands while you are looking for the inlet or outlet. Here, the GPS is a perfect problem-solver, although if it’s an old one you have to plot lat and long very accurately – not always easy in a canoe – and you have to set it up referring to the Grid system. Much easier if the unit has a moving-map.

 

     Cellphones are not yet perfect as a GPS source as of 2018. Many programs require access to a cellphone network in order to function – and those will be non-existent in the back-country for many years to come. There are many navigation-apps. You will have to test yours to see if it works in a “dead-zone”. Also, some apps require the program to be open and functioning when you move into that dead-zone, or into airplane-mode.

  Also, most dedicated GPS receivers use far less power than a cellphone. A couple of AA batteries can last for days. Charging a cellphone is not easy on a Bush trip.

     A compass is an essential back-up. I generally have one in my pocket and a spare in my pack, and a mickey-mouse one on a zipper pull-tab or two. But since most of the same destructions can happen to it, the idea of using the sun can be useful.

     A map is critical. One thing I would never do is depend solely on the database in a GPS unit for navigation information. There should be paper (or these days, perhaps Tyvek) maps. For accurate orienteering I prefer the 1:50,000 topo maps. These show every tiny wiggle of the earth. On long trips you need a stack of them and that costs a lot, but better that than getting lost. (I hate getting lost, and yes, I’ve been temporarily uncertain of my exact location more than once!) These maps can now be downloaded, or purchased on a CD and home printed [see Sources]. This is very useful for customizing a route such as following a river. (It seems every place I want to go is the joining of 4 traditional maps!) But beware! A home printer does not usually have waterproof ink! It would be a disaster to have your trip maps dissolve into a multi-coloured stream of flowing ink.

     Waterproofing maps is a good idea. There are various specific liquids you can purchase for this. But other compounds can suffice: Thompson’s water seal, plastic ignition-sealing spray, canvas tent-waterproofer wax solution and so on. Find out what is in your home area and test-waterproof your maps. In use, I sometimes use one of the bought plastic sleeves to store the maps in, but these become scratched and dirty with time, and sooner or later the map comes into your hand and gets rained-on.

     Important too, is to have a spare. I generally have the next-size-up (1:250,000 map coverage) in the other party’s canoe or sled or stuffed in a pack. On some trips down large rivers, with big distances traveled each day, this map scale may suffice. Also, in the far north, 1:50,000 map coverage has not yet been completed for the entire country. Careful: dangerous places may not be sufficiently identified. Rapids and waterfalls are not always portrayed on the big map very clearly, and of course are not always seen when actually paddling until it’s too late and you’re committed. If I had only 1:250,000 maps, I’d want a very good guidebook close to hand.

Distance Measurement. I’m hopeless at counting steps. It should be easy, and I should do it as a matter of habit, but I can’t. I daydream and lose track. (Was that 500 or 600? Oh darn!)

     It is good to measure your standard rate of walking or paddling, in good conditions, no wind, water calm or good footing, but this can change wildly with conditions.

     What I do is reference myself to large landforms, or large changes in direction. There may be a big hill in the distance, or cliffs, or a set of islands (and so on) that can give you an overall idea (in conjunction with the map) of how fast you are moving. Also, general orientation of the land or water: if the lake lies generally southwest, but gently curves around to the northwest over the space of 20 miles or so, your heading can give you an idea of how far along you are. If you’re walking in dense bush, have a look first to see if the map shows ridges and valleys in any general pattern – often the glaciations of past ages have left the earth marked. This can aid you during a bushwhack (eg. If the map shows you’ll generally be climbing and descending ridges on a 45, this helps a great deal as you wiggle around the trees.)

 

Aim to one side. If you want to bushwhack without-GPS to a specific place along a lakeshore or riverbank, don’t aim straight for it. The odds are you won’t be dead-on, thus when you get to the shoreline you won’t know which way to turn. But if you’ve aimed deliberately half a klick to one side, you’ll have a pretty good idea. This seems wasteful, but it calms the mind to know exactly where your destination lies. It’s worth it.

 

     By the way – “orient” or” orientate”? It depends on the continent. The Brits say orientate as a verb. Americans tend to say orient. It doesn’t matter – either is better than saying, “We’re lost!”

 

 

 

 

 

 

 

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