Altona Meridian
Coordinates: 53 ° 32 '49.9 " N , 9 ° 56" 32.4 " E
The Altona Meridian was the baseline for the measurement of the entire Danish state and Altona as well as for the topographical mapping of Holstein , Hamburg and Lauenburg according to the triangulation method by the astronomer and geodesist Heinrich Christian Schumacher in the 19th century. Schumacher determined this value for the place where he had set up his observatory to be 30 '25' 'east of Paris in time , expressed in terms of the 24 hours of an earth's revolution , as the time difference between the passes of the midday height of the sun in Altona and in Paris.
The reference to Paris resulted from the fact that the Parisian meridian was the most widespread in mainland Europe during Schumacher's time, until the International Meridian Conference of 1884 declared the prime meridian of the Royal Greenwich Observatory to be generally binding.
The value of 0 s ( hours ), 30 '( minutes ) 25' '( seconds ) determined by Schumacher corresponds to the value of 7 ° 36' 15 '' (based on Paris) in today's standard geographic longitude . If you add the difference in length from Paris to the Greenwich meridian (2 ° 20 '14' '), the result for the reference location chosen by Schumacher is the value of 9 ° 56' 29 '' east of Greenwich. Today's more precise measurements give the value of 9 ° 56 '' 37 '' east longitude for the same location.
The Altonaer Meridian is marked today by a bronze rail embedded in the ground at the Königstraße stop of the Hamburg S-Bahn (exit Struenseestraße) with the inscription Altonaer Meridian 0s 30 '25' 'east of Paris . A vertical continuation runs on the wall of the stop structure, next to which there is also a memorial plaque for Heinrich Christian Schumacher. The Altona observatory , which was set up by Schumacher at the time, was located on Palmaille Street, south of the aforementioned stop . On the slope to the Elbe , below this place there is / was another marker.
literature
- Gerd Hoffmann; Karl-Heinz Nerkamp. Heinrich Christian Schumacher - The Altona Astronomer and Surveying , GV current special issue; State Office for Geoinformation and Surveying, Hamburg 2009 (digitized version)