Astronomical level

The astronomical level is a method of astrogeodesy for the exact determination of the course of the level surface between survey points. At each point of the measurement profile, star passages are measured using theodolite or prism astrolab and the plumb lines of all points are calculated from this. The area which is perpendicular to these perpendicular directions is the level or equipotential area sought.

The method corresponds to a refinement of the previous degree measurement and can also be carried out in intersecting lines (i.e. two-dimensional) instead of in profiles. In this form it is used for local or regional geoid determination .

Depending on the shape of the terrain and the geological subsoil, the curvature of the level surface deviates slightly from the mean curvature of the earth , from which the rock density and structures in the subsurface can be calculated with high measurement accuracy .

See also

• Astronomical latitude and longitude
• Method of equal heights
• Geoid study
• Geophysical prospecting

literature

• Karl Ledersteger : Astronomical and Physical Geodesy ( Earth Measurement ) , Chapter IV (Vertical Deviation and Geoid). Jordan-Eggert-Kneissl Volume V, Handbook of Surveying, Verlag JB Metzler, Stuttgart 1969
• Bernhard Heck: Calculation methods and evaluation models for land surveying , 3rd edition, Wichmann-Verlag, Karlsruhe 2003