Due to its exposed location and its importance as a winter sports area, it is far better known than the two-metre higher Langenberg. Just like the Kahle Pön and the Ettelsberg near Willingen, remnants of a high heath landscape have also been preserved here. The Kahler Asten area is also part of the main watershed between the Rhine and Weser river systems. The Lenne has its source not far from the summit. The spring, which only carries water periodically, is located at an altitude of 835 m above sea level, making it the highest spring in the Rothaargebirge. From the Astenturm tower, you have an excellent view of the Rhenish Slate Mountains. In good weather, you can even see the Großer Feldberg in the Taunus and the Wasserkuppe in the Rhön. The summit of the Kahler Asten rises around 3.3 km south-west of Winterberg town center between the districts of Altastenberg to the north-west, Neuastenberg to the south and Lenneplätze to the south-west.
Geology: The Kahler Asten is predominantly composed of slate claystones and quartzitic sandstones from the Middle Devonian period. They were given the name "Asten layers" due to their characteristic formation on the Kahler Asten. The quartzites are an ideal building material due to their great hardness and bank-like formation. The foundations of the Astenturm are also made from them.
Age of the rocks: Asten layers: Upper Eifel stage, Middle Devonian (around 388 million years before today)
Use of the rocks: Numerous quarries exist in the region around Winterberg, where the sandstones and quartzites of the Asten layers were extracted for building houses and as gravel for roads.