22
Aug
2011
4

Forgotten your compass? Use the sun to navigate

Jason Ingamells from Woodland Ways is our guest blogger today

Jason Ingamells from Woodland Ways is our guest blogger today

The sun’s path through the sky is completely predictable and if we become familiar with its movements it can be used to navigate quite accurately. So what is its path through the sky?  Ask most people and they will say it rises in the east, passes overhead at noon and sets in the west but there are several inaccuracies in this statement.

Here, Jason Ingamells of Woodland Ways, one of the UK’s leading Bushcraft experts, explains how you can navigate using the sun.

Because of the tilt of the earth and our latitude in this country the sun only ever rises exactly east and sets exactly west on the spring and autumn equinoxes.  On the summer solstice it actually rises almost north-east and sets north-west, whilst on the winter solstice it rises roughly south-east and sets south west.  The same factors (tilt and latitude) also mean the sun never actually passes directly overhead but is always to the south of us even in midsummer. There are also slight variations in the spin of the earth which mean that the sun isn’t always at its highest point at exactly noon as one would imagine, it can actually by up to about 15 minutes before or after noon when it’s at its highest. In addition in summer by moving the clocks forward by an hour things get even more complicated.

So if all this sounds confusing it can be simplified very easily. The earth always makes one complete revolution every 24 hours (give or take a minute or two) so the sun appears to move through the sky 360 degrees over the same period, so about 150 an hour.  So regardless of the time of year and even at night when you can’t see it  the sun will be approximately  north-east at 3am, east at 6am, south east at 9am, south at midday, south-west at 3pm, west at 6pm, north-west at 9pm and believe it or not north at midnight. The only thing to remember is to add an hour on during British Summertime or always work on GMT. So although this is not nearly as accurate as navigating with a compass it means that if the sun is out and you have a watch it is possible to get a good idea of direction using the sun.

If all that is a lot to remember, a quick way to get your bearings that works well between 6am and 6pm is to use your watch.  Provided your watch has hands and isn’t a digital watch (in which case simply improvise by drawing it out on a piece of paper), point the hour hand at the sun and bisect the angle between the hour hand and the 12 on the watch dial (1 during BST). This will give you a north-south line. As we know that in the UK the sun is always in the southern part of the sky between 6am and 6pm then we can find south and calculate the other cardinal points.

How to use your watch to find the directionA more accurate way that takes a bit more time is to use a shadow stick.  Place a thin straight stick in the ground and mark where the tip of its shadow ends.  Wait a suitable period of time….the longer the better and ideally an equal time period either side of noon. The shadow will have moved as the sun has progressed through the sky, if you mark the shadow now, the two markers will give you an approximate west-east line meaning if you stand along it with your left foot nearest to the first marker and your right next to the second you should be facing due north.

To get an exact north bearing, mark the shadow every few minutes for a hour or so spanning noon (1pm in summer) and determine where the shortest shadow is. This will be when the sun was at its highest which is when it is exactly south in the sky hence the shadow will point exactly due north.

A shadow stick is a more accurate way of navigation with the sun

 

Have you had to use the sun for navigation? What else in the natural world do you use for navigation when your Ordnance Survey map & compass or GPS device aren’t at hand?

And if the sun has already set, here’s some advice on using the stars for navigation.

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Stay safe and brush up on your map reading skills

11 Responses

  1. There’s never much sun around when I need help with navigation, when the sky is clear I can usually see something, otherwise hearing and smell can be helpful. A distant train can indicate direction when visibility is poor. Smell can work too, my son can tell precisely what direction to walk to find a KFC in a two or three mile radius.

  2. Pingback : Working with Ordnance Survey on Navigation

  3. If you’d like to know more about the subject, you might enjoy the book I wrote about natural navigation, it’s called The Natural Navigator. Lots more info on the website too.

  4. @malcolm, great tip, thank you.

    @Martyn maybe your son could write us a ‘how to navigate via fast food’ post?!

    @Tristan your site is excellent, thank you for sharing it. If you’d be interested in writing something for us let me know.

  5. @Tristan Just ordered your book plus a copy for my Dad, I love your website, particularly Whale Navigation which will tease scientists for years to come (perhaps Whale Sonar can “great circle” the earth). Your page on Celestial Navigation reminded me of Dad’s Bubble Sextant which he taught me to use in my early teens. I retook the RYA Yachtmaster course when my own son was 18 but sadly Celestial Navigation is no longer trained.

    Apologies to OS for hijacking their story but you asked for alternative methods of navigation and @Tristan offers superb examples on his website.

  6. Do you mind if I quote a few of your posts as long as I provide credit and sources back to your website? My website is in the exact same niche as yours and my users would truly benefit from some of the information you present here. Please let me know if this okay with you. Appreciate it!

    1. Gemma

      Hi
      Yes, provided we are credited and there is a link back to our blog post, more than happy for that to happen.
      Thanks, Gemma

  7. Pingback : Your shadow is your compass | Conversations with Dio

  8. Rob

    Interesting article but I would have thought that the logical follow on to this was not just the offered one about star navigation but also lunar navigation. I would be willing to write a short piece about if that would be helpful.

    Natural Navigator book is interesting but does contain some errors.

    Would be helpful if the blog could be edited to make it clear that when it says 150 (in para 2) what is actually meant is 15 degrees.

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