From Skibergfjell, the circumference of the earth was measured

Sometimes local cultural monuments can have a long reach. On top of the popular hiking area Skibergfjell stands a seemingly simple granite column with an elongated history.

Right from the Greek Eratosthenes counted the earth's circumference with only one cane 200 years BC. and until today, many different methods have been used to calculate the earth's size. The hexagonal granite column on Skibergfjell represents one of them.

 

In the 1860s, the European Graduation Commission started an international project to better determine the shape and size of the earth. Along the whole of Europe from Sicily in Italy to Levanger in Nord-Trøndelag, points were used in the measurement work. The column on Skibergfjell was erected in 1876 and is part of this elongated network. Similar pillars are also found elsewhere in the country, including at Gelinåsen in Hurum, but there should also have been points on known mountain peaks such as Gaustatoppen, Kolsås, Oppkuven, Spåtind, Tronfjell and Ronden.

 

By building up a network of points and measuring angles between them in addition to a few distance measurements, one could finally calculate the length of the entire stretch. The length one came to be was then combined with astronomical width and length to determine the shape and size of the earth. In the latter half of the 19th century, one had good knowledge of the extent of the earth, so the purpose of the project was to investigate how well the ellipsoid of the time (a mathematical surface used to calculate height above sea level) actually matched reality. Norway's contribution was to measure the stretch from Svinesund to Levanger.

Granittsøyle Skibergfjell
Granittsøyle Skibergfjell
Photo: Holmestrand kommune

However, the history of Skibergfjell as a measuring point does not end there. A 10-20 meters away from the granite column stands a square column of concrete. In order to be able to make accurate and detailed maps of Norway in the 20th century, it was first necessary to establish a network of trigonometric points, ie, a triangular network with points where the coordinates were known. The points were often laid on heights, hills and mountains with good views where one could look at other trigonometric points. The concrete column was built as part of what is called the first-order foundation network, later the backbone. The first and most rough mask of the triangular networks. Later, more and more fine-meshed networks of trigonometric points were created covering the whole country.

 

But also near our own time, Skibergfjell has been actively used in surveying. Just a few meters from the concrete column, a metal bolt is inserted into the rock. GPS measurements were carried out here in the 1990s. Skibergfjell has thus been an important point in the geodetic foundation network for 150 years.

 

To get to Skibergfjell you have to drive towards Eidsfoss along the west side of Bergsvannet and take off at Brekkeveien. Quite soon you get to a pay toll, it costs NOK 80 to pass, but it's well worth the money for the ground up is long and hard. From the parking lot it takes approx. 1 hour to go up to the top of Skibergfjell. Don't forget to visit Vestfjellet as it is now fixed as Vestfold's highest mountain. If it has rained then please bring shoes that can withstand water for some parties can be very soft.

 

Use the last fine days before the winter comes and take the trip up to Skibergfjell from where you once measured the earth's circumference.

 

Source: Municipality of Holmestrand

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