sea level
Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardise ...
, the Rehberg in the
Harz mountains
The Harz () is a highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The name ''Harz'' derives from the Middle High German w ...
is the fourth highest mountain in the German state of
Lower Saxony
Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state (') in northwestern Germany. It is the second-largest state by land area, with , and fourth-largest in population (8 million in 2021) among the 16 ...
, and the fifth-highest in the Harz.
Location and access
It is located in the
Harz National Park
Harz National Park is a nature reserve in the German federal states of Lower Saxony and Saxony-Anhalt. It comprises portions of the western Harz mountain range, extending from Herzberg and Bad Lauterberg at the southern edge to Bad Harzburg ...
immediately north of
Sankt Andreasberg
Sankt Andreasberg is a former town in the district of Goslar, in Lower Saxony, Germany. Since 1 November 2011, it is part of the town Braunlage. It is situated in the Harz, approximately 7 km west of Braunlage proper, and 20 km east ...
. Its summit is a broad, flat dome, much of which is forested. It is not easily accessible because the route from the Rehberg 'ski cross' (''Rehberger Skikreuz'') was renaturalised several years ago by the Harz National Park as part of its nature conservation planning. In addition, in the region of the summit a marsh biotope has been created by artificial water damming. Along the mountain's eastern and southern sides run two tracks: the '' Rehberger Grabenweg'', with its tavern, the '' Rehberger Grabenhaus'' (checkpoint 155 in the
Harzer Wandernadel
The Harzer Wandernadel is a system of hiking awards in the Harz mountains in central Germany. The hiker (or mountain biker) can earn awards at different levels of challenge by walking to the various checkpoints in the network and stamping his or ...
system. Higher up is the ''Rehberger Planweg'' which takes walkers and cross-country skiers around the mountain.
Observatory
Due to its location and the lack of habitation on and around the Rehberg, it has an almost natural dark night sky with a
surface brightness
In astronomy, surface brightness (SB) quantifies the apparent brightness or flux density per unit angular area of a spatially extended object such as a galaxy or nebula, or of the night sky background. An object's surface brightness depends on ...
of 21.75 mag/arcsec². For this reason the Sankt Andreasberg Observatory Society (''Sternwarte Sankt Andreasberg e. V.'') selected a building on the southwestern part of the mountain as the site for its barrier-free observatory.