Castanea and the Bessel ellipsoid
In Castanea delle Furie there is "l'ugghia", or "the needle", one of the three points in Italy used for the calculation of the Bessel ellipsoid.
The Bessel ellipsoid, also known as Bessel 1841, is a reference ellipsoid used for Europe. Friedrich Wilhelm Bessel calculated this in 1841 from a large compendium of topographical data in Europe, Russia and India. Its design is based in total on the length of ten meridian arcs and 38 precise measurements of latitudes and longitudes. Currently the Bessel ellipsoid is used by several countries for their national geodetic surveys, but it will be replaced in the next decades by the modern ellipsoids of satellite geodesy.
Castanea delle Furie is one of the three points in Italy used by Bessel for the calculation of the ellipsoid. This point is called in dialect "Ugghia" to indicate that at its top there must have been an "Ago". The other two points in Italy are located in Turin and on Monte Mario in Rome.
