To use a sun compass you must know the time, and therefore you must have a watch or a radio.
So how do you find the North with a sundial, without knowing the time?
The answer is clever: you need to have two, of different types.
From the book Les Cadrans solaires by Denis Savoie
On the same board, a classic horizontal sundial and an analemmatic dial are built.
There is no question about the Vikings having such a compass: the analemmatic dial was invented in the seventeenth century (unless there is a new revelation about the incredible scientific level of the Vikings, of course!). See the article on the (potential) Viking solar compass
The board is turned until both dials indicate the same time. At this point, the style of the horizontal dial indicates North.
Difficult to use in practice, as these dials are only valid for a given latitude. If you are not sure of your position, you should have several…
| Finding North without a compass All articles |
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1 |
With a stick (and the day) |
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2 |
With a stick (and 30 minutes) |
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3 |
With a regular watch |
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4 |
With a pilot watch |
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5 |
With a double sundial |
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