What is a gnomon and what is it for –

His name is already rare in itself, we know. But this thing, which has the name of a fictional character or an imaginary virtual currency from a game of dungeons and dragons, is a very interesting instrument that has its magic and you’ll be amazed when you meet it. In this post we will explain in detail what is a gnomon and what is it for. As an advance, we tell you that it is one of the oldest gadgets in history.

what is a gnomon

Despite its charismatic name, the gnomon is actually a super simple object. A simple stick stuck in the ground. No more. The Egyptians used it but also other societies and cultures such as the Babylonians, the Chinese and pre-Columbian cultures already trusted in the effectiveness of the rod.

It is a word that comes from the Greek and means needle. The peculiarity of this water is that it forms part of a sundial or quadrant. Thus, we are facing a sundial or part of it. An instrument that was of great importance years ago, when other more sophisticated mechanisms like the ones we have now had not been invented.

What is a gnomon for?

The gnomon was nailed to the ground vertically and marked the position of the sun. How is this? Easy! By giving it sunlight, the gnomon projected a vertical line or shadow on the ground, which changed its length and position as the sun changed places on its path around the Earth.

There are several models of gnomon that work differently depending on the type of compass. On the one hand, we have the Kepler model and on the other, the Obelisk. The first thing, in any of the cases, is to place the point of the arrow of the compass in the number 12 of the quadrant. The solar time will be the one that marks the shadow of the thread.

In the Kepler model, the viewing hole of the Arrowhead has to connect with the North of the Compass Rose. So we can know the other 32 remaining addresses. In the obelisk model, we put the watch horizontally orienting the point of the arrow of the needle towards the North. Now we will place it vertically with the gnomon just at the latitude of the place where we are.

In short, with the gnomon we can: know the height of the Sun, determine the meridian line or North-South, as well as the latitude. In addition, it allows us to know the solar declination, trace the solar analemma and know the height of objects.

Now you have learned a little more about astronomy and can speak properly when you see, read or hear about the what is a gnomonits mechanism, its origins and usefulness.

You enjoy history? We invite you to learn more about a very important and interesting period such as the Enlightenment:

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