What is and what purpose does a gnomon serve?
A gnomon is an geometrical element used mainly in astronomy and geometry to determine time and directions. It may adopt various forms, ale most frequently it is a straight, vertical bar or pole which casts a shadow to the surface on which it is placed.
In astronomy, a gnomon is used for determining time by means of a solar disc or a sundial. A gnomon indicates hourse on the basis of the movement of the shadow which is cast on the scale or disc placed on the horizontal plane.
In geometry, a gnomon is defined as a part of a geometrical figure which is left after removing some smaller shape from a bigger one. For example, if we remove a square from a rectangular, we obtain a gnomon.
The term “gnomon” is also used in other fields, such as archaeology, where it refers to the vertical part of ancient sundials or other measurement instruments.
How does a gnomon work?
A gnomon work on the cast shadow. When sunlight falls on the gnomon, a shadow is created. The shadow is cast onto the surface where the gnomon is located. Based on the movement of this shadow, you can read information such as time and directions.
In the case of a sundial, the gnomon is positioned vertically on a horizontal plane, which is calibrated in hours and minutes. When the sun shines on the gnomon, it casts a shadow on the sundial scale. As the sun moves across the sky, the shadow moves along the scale, indicating the current time. The highest point of the shadow indicates solar time, and the shadow moves as time passes.
In astronomy, a gnomon can also be used to determine directions. If we know a specific time, we can observe the angle at which the shadows of the gnomon fall to determine the north-south direction. On the summer solstice (in the northern hemisphere), when the sun reaches its highest point in the sky, the gnomon’s shadow is shortest and points north. However, on the winter solstice, when the sun reaches its lowest point in the sky, the gnomon’s shadow is longest and points south.
Gnomon in Muchów and other nearby attractions
In Muchów in the “Chełmy” Landscape Park, the gnomon is positioned at the intersection of the 51N parallel with the 16E meridian It is located approximately 2 kilometers from National Road 365. A well-maintained gravel road leads to it. Next to the gnomon, informative educational boards have been set up, along with benches and tables.
Other attractions near the gnomon in Muchów are:
Interesting facts
- A gnomon is one of the oldest tools used by human to measure time. The first sundials that used a gnomon appeared in ancient times.
- The word “gnomon” originates from the Greek language and means “indicator” or “sign”. This term was introduced by the Greek mathematician Heron of Alexandria.
- In ancient Egypt, the gnomon was used to measure the height of the Nile, which was essential for planning the irrigation of agricultural fields.
- Gnomons were widely utilized by ancient Greeks and Romans. They were used not only for measuring time but also for determining the dates of solstices and equinoxes, as well as for astronomical observations.
- Gnomons are still used in some places around the world as components of sundials. An example is the famous Prague Astronomical Clock, which uses a gnomon to indicate time.
- The gnomon is also present in some contemporary architectural projects and sculptures, where it can serve decorative or symbolic purposes.
- The gnomon can also be used to determine geographic latitude. In the case where we know the exact time and date, by observing the shadow of the gnomon at a specific location, we can approximate the geographic latitude.
