Sunday, September 23, 2012

Using a Compass - Backstopping

The best way to deal with getting lost in the wilderness is to not get lost in the first place.  To this end you should always carry a compass and preferably a topo map when headed out into the wilds.  In these modern, hi-tech times many people carry a GPS unit, or have GPS on their smart phones.  I wish I could tell you more about these but you're talking to a guy who only got his first cell phone last year when forced to do so by his loving wife.  I've always held to the belief that simpler is better and more reliable.  An old time magnetic compass doesn't have any batteries to go out, it keeps working after you've fallen into a stream, and you have to bang it pretty hard to break it.  A compass alone is not nearly as useful as a compass used in conjunction with a map, but a compass can keep you going in a straight course which is very hard to do otherwise.

One technique that you can use to keep yourself found with only a compass is called backstopping.  Backstopping cannot be used in every instance but it can be used in many.  Here's how it works.


Let's say that you are going hiking in an area that you are unfamiliar with.  All you have is a compass; no map of the area other than the road map or GPS in your car that you used to get to the area.  You arrive at your take off point, say a road-side parking area, and prepare to head out into the woods.  Look at your road map or the GPS screen in your car and see if the road continues in a fairly straight line in both directions from where you are standing.  If it does, the road can serve as your backstop.  Let's say that the road runs pretty much North and South, and you are going to be hiking in an area that is east of the road.  Take a compass reading to verify that you are heading out on a course of, in this case, 90º.  If you become lost or disoriented on your hike, you can follow a compass course of 270º and you will eventually hit your backstop.  This method has its drawbacks.  When you do hit your backstop, you may not know whether you are north or south of the place where your car is parked; but you're still better off than you would be wandering around in the woods.  Railroad lines, utility lines, and pipelines all make good backstops.  They usually follow a straighter and longer course than the average back-country road.


Let's take the same scenario as above and assume that you do have a topo map with you.  You hike for several hours and decide it's time to head back to the car.  You orient your map and take bearings on a couple of landmarks to fix your position.  Now you can set a compass course straight for your vehicle.  So you follow your course, hit the road, and there's no vehicle.  Now you don't know if you parked farther to the South or to more to the North of where you came out onto the road.  We've all been there.  There's no way to follow a compass course with that much accuracy over broken ground.  Here's something you can do to help minimize this problem.  Set a course that will deliberately miss your target either to the North or to the South.  If you haven't gone very far into the woods, you may want to aim for a point, say, half-a-mile north of your vehicle.  When you hit your backstop you know that your vehicle is going to be to the south.  The farther away from your target you are, the farther North or South your point of aim should be.  This will help guarantee that variations in your course will not put you on the wrong side of your target.

Monday, September 10, 2012

Telling Time by the Stars

The title of this post is a little misleading.  What I'm really going to show you is how to tell how much time has passed rather than how to tell the exact time.  This is a little trick that my grand-dad taught me when I was a boy.  Grand-dad was a cowboy back in the late 1800's.  In those days a time-piece was an expensive luxury that most working men didn't own, and if a man did have a watch he certainly didn't wear it when doing range work.  But cowhands still had to have some way of telling the approximate time at night so they would know when to change guards on the herd. Here's how they did it, and how you can do the same.  By the way, this only works if you live in the Northern Hemisphere.

First you need to locate the North Star (see my post of 9/3/2012).  Now look for the two constellations Cassiopeia (shaped like the letter "W") and Ursa Major (the big dipper).  If you live in the lower latitudes, like the southern United States or Mexico, you may not be able to see both of these constellations at the same time.  That's not a problem.  As long as you can see one of them this will still work.

OK, the North Star, because it's located directly above the North Pole, appears to stay in the same position in the sky at all times.  The constellations Cassiopeia and Ursa Major appear to rotate in a counter-clockwise direction around the North Star, and they make one complete trip around the North Star every twenty-four hours.

So the first thing the old cowboys would do was take note of the position of the constellations when they went out on night watch.  Pictured below: How the stars might have looked at the beginning of night watch

When the constellations had moved forty-five degrees around the North Star, the cowhand knew that three hours had passed. Pictured below: Position of the constellations three hours later

When the constellations had moved ninety degrees around the North Star, he knew that six hours had passed.  Pictured below: Position of the constellations six hours later

With a little practice a man could tell the passage of time with surprising accuracy.  In the example I just gave I used three hours and six hours to make it easy for you to visualize.  In the old days, night watch was usually in four hour shifts; and the cowboys could read the stars accurately enough to get their timing pretty close to right.      

Monday, September 3, 2012

Finding Direction at Night Using the North Star

It is not a good idea to travel at night in the wilderness unless you are in desert terrain, but night-time is a good time to orient yourself and figure out directions.  In the Northern Hemisphere the North Star (Polaris) has been used for thousands of years to establish which direction is north.  Contrary to popular belief, the North Star is not the brightest star in the night sky.  In fact there are forty-seven stars that are brighter than the North Star, so we must use some method other than brightness to locate the North Star.  The North Star is at the end of the handle of the constellation we call the Little Dipper (Ursa Minor).  Unfortunately, the stars of the little dipper are not very bright, and this constellation can be difficult to locate.  Two easily identifiable constellations will help you locate the North Star.  One of these is the constellation that we call the Big Dipper (Ursa Major).  If you draw a straight line through the two stars at the end of the cup in the dipper (called the pointer stars), the line will point toward the North Star.  The distance to the North Star is about five times the distance between the two pointer stars. 

Depending on the time of night, the month of the year, and your own latitude; the Big Dipper may not be visible to you.  If this is the case you can look for the constellation Cassiopeia. Cassiopeia also revolves around the North Star and is located on the opposite side of the North Star from the Big Dipper.  Cassiopeia looks like the letter "W" or the letter "M" depending on where it is in its path around the North Star.

Once you have located the North Star you can take a sharp stick and draw a line on the ground.  Draw the line from where you are standing so that it points toward the north.  Label the end of the line that points toward the star with an "N".  Label the other end of the line with an "S".  Now draw another line that crosses your north/south line at a ninety degree angle.  As you face the north, the right end of your second line will be pointing to the east.  Label it with an "E".  Label the other end of this line with a "W".  Now get a good night's sleep and when you wake up in the morning you will have a compass drawn on the ground that will help you get started in the direction you want to travel.