Copyright: Région Franche-Comté, Inventaire du patrimoine
The prism astrolabe of Auguste Claude, deputy member of the Bureau des Longitudes, and Ludovic Driencourt, chief hydrographic engineer of the French Navy, was used to determine the geographical coordinates of a place (Gauss method) by combining the culmination time, which gives one of the coordinates, and the height of the object (declination), which gives the other. The version built by Amédée Jobin included adjustment and lighting facilities, among other improvements. This version has become the favorite among surveyors and travelers.