Picture of Make a Viking Sun Compass
Imagine the situation - you're due to go on a raid tomorrow, but Bjorn Hammersson won your lodestone in a game of hnefetafl last night. No magnetic lodestone, nothing to indicate North when you're out of sight of land. How are you going to find your way at sea?

Fortunately, with a nail, a lump of wood and a few spare hours, you can construct a sun compass.

(To do this Instructable properly, it is not absolutely vital to be wearing a Viking helmet, but it helps. It's a long time since mine last came out of the shed...)
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Step 1: Make your Sun Compass.

Picture of Make your Sun Compass.

Bang the nail through the piece of wood. No, don't use a rock, you're supposed to be civilised. Use a hammer.


Yes, really, you're done. All you need to do now is calibrate it.

Step 2: Calibrate your sun compass.

Picture of Calibrate your sun compass.

All you need is patience and a pencil.

Put your sun compass somewhere that is both sunny and won't be disturbed, or where you can make sure that you place the sun compass in exactly the same orientation each time. I stood mine on an up-turned planter, to stop folk stepping on the nail.

Spend the day near your sun compass, doing useful things to prepare for your raid (mending sails, sharpening swords, doing careful stretching exercises so you don't pull a muscle during an important ravish, you know the kind of thing).

Every so often (try for every 20 or 30 minutes, but at least every hour), mark the tip of the nail's shadow with your pencil.

At the end of the day, join the marks in a smooth curve, known as the gnomon curve.

Find the point where the gnomon curve passes closest to the nail. Draw a straight line from that point to the base of the nail. That will be your North-South line (as a Viking, living in the Northern hemisphere, North is pointing away from the nail. If you are making your sun compass in the Southern hemisphere, North is pointing towards the nail, and you must be the most utterly-lost Viking in history).

Step 3: Using the Sun Compass.

Picture of Using the Sun Compass.

There you are, out at sea, no land in sight - where's North?

Hold your sun compass upright and look for the shadow of the nail. Turn (not tilt!) the compass until the tip of the shadow just touches the gnomon curve. The line you originally drew from nail to gnomon curve will now be pointing North - happy sailing!

Step 4: A Warning ...

Picture of A Warning ...
Obviously, the height of the Sun changes throughout the year, so your sun compass will only be accurate for a few days.

It won't make much difference at first - you'll still get back to a recognisable stretch of coast and be able to find your way home by eye, but eventually it will be way out.

The solution is to create a larger sun compass, with a lot of gnomon curves on it - at least one per month, preferably one per week, and certainly one on each solstice and the equinoxes. Mark the gnomon curves clearly with the date they were drawn, and then, in future years, you can use the same sun compass year after year.

Copy the pattern carefully, carving into the prow of your dragonship, and you'll never get lost again, no matter what Bjorn's luck with at the table...

acoleman34 months ago

interesting, but you're only half right. yes, it was a navigational instrument to determine a course, but it wasn't used to determine what way was north. the gnomic lines terminate prematurely and would make it impossible to determine north in the late afty. another problem is the marks were a few degrees off, which would have put them many miles off course. researchers believe it's actually a sun shadow board, used to find local noon and calculate latitude. it had two gnomons, one taller than the other. the short gnomon was used to determine noon and the taller one used to find the current latitude. this would give a deviation of no more than 6 nautical miles (11km) and between greenland and norway, that deviation's not a big issue.


SparkySolar9 months ago


Kiteman (author)  SparkySolar9 months ago


Bill WW1 year ago
Great Instructable and very fun to read.

On a large flat Viking ship the shadow of the tip of the mast could be drawn on the deck and a gnomic curve drawn. With the north point marked, the other compass points could also be inscribed on the deck. Then the Viking captain would just leave Stavanger and head south-south-west.

Just saying.
i really enjoy your historical accuracy regaurding norse viking culture its good to see other people recognizing it as it is
Kiteman (author)  Erod D-Isle1 year ago
Er... thank you?
sorry its a thing i have how people have strayed from their natural purpose and a viking thing a little too
InTheory1 year ago
Protip: if you can fix a gem of iolite (cordierite) to the top of the nail head it can show where the sun is in even the cloudy days.

Thanks for the instructable, when I find the iolite I have been hoarding away this will be invaluable!
Kiteman (author)  InTheory1 year ago

Oh, yes!
Ginyb1 year ago
If I live in Bakersfield, CA and there is a need for this where is my north. could you tell me where I could get more info. thanks ginyb
Kiteman (author)  Ginyb1 year ago
I'm afraid I don't know what you're asking me - do you want to know where North is from where you are?
This Bakersfieldian is obviously not of Viking decent... :P Great tool Kiteman!
ilpug Ginyb1 year ago
If you live in Bakersfield, I would advise that your North is any direction that leads out of Bakersfield...
blkhawk1 year ago
Viking helmets did not have horns! Your picture is historically inaccurate! :-P
He just happens to be hornier than...most Vikings? wait, that didn't sound right either...
LOL! Good one! :-)
Kiteman (author)  blkhawk1 year ago
My sources say differently:
You beat me using the Sunday Comics! You don't play fair!
Kiteman (author)  blkhawk1 year ago
snotty blkhawk1 year ago
Space viking helmets have horn-like antennae.
snotty snotty1 year ago

Kiteman (author)  snotty1 year ago
SHIFT!1 year ago
This will be great when I inevitably get lost in the woods!
Kiteman (author)  SHIFT!1 year ago
Don't forget, though, you'll need to stay put for a full day to calibrate it.
SHIFT! Kiteman1 year ago
Ooh, good point! I'll need to pack a can of Anti-Bear Spray then.
This reminds me of a sun compass I make. You put a stick in the ground, mark where the tip of the shadow is, wait 15 minutes, then mark were the tip of the shadow is again. You connect the two points, and that's your east-west line. You intersect that line to make your north-south line.
Kiteman (author)  Mr_Altitude1 year ago
That's OK for survival navigation, but that line should be a curve - you wouldn't be able to navigate to a specific point, but you would be able to find your way out of a desert.
PKM1 year ago
I wonder if there's such a thing as a calculator or spreadsheet which can take your latitude and generate gnomon curves for various times of year? The fun is probably in making the curve yourself but it would be interesting to see how they change with latitude and season.
Kiteman (author)  PKM1 year ago
I've seen sundial generators, the curves would be the same.
Pretty cool! ManVS.Wild!
Kiteman (author)  nerfrocketeer1 year ago
Hehe, thanks!
ehudwill1 year ago
Great instructable. Fun to read and informative.
Kiteman (author)  ehudwill1 year ago
Thank you!
JMRaphael1 year ago
Awesome project! In scouting, one skill similar to this involved using a stick placed at the center of a clock face to point North. Always good to see tools that serve an efficient, practical purpose with a minimum of resources!
Kiteman (author)  JMRaphael1 year ago
Thank you!
rimar20001 year ago
Interesting. But the height of the Sun changes not only throughout the year but with latitude. It is to say: this compass is perfect if you travel along a parallel (east to west or viceversa) , but otherwise it would bring erroneous data. Anyway, clever device.
Kiteman (author)  rimar20001 year ago
Sometimes just landing on the right continent is a plus!
Dang that Bjorn Hammersson! This is really useful, and a nice activity on a sunny day. Thanks.
Kiteman (author)  mandolinible1 year ago
You're welcome!