Main astronomical point of Bulgaria

The Astronomical Tower, also known as “The Main Astronomical Point of the State Triangulation of Bulgaria,” is a hexagonal structure located behind Sofia’s Central Military Club. This marks the beginning of the design and measurement of state triangulation. Originally, it was employed to undertake astronomical observations in order to ascertain geographical coordinates. Acad. Vladimir Hristov estimated its longitude (23o 33′) in 1930 using bilateral observations with the Prussian Geodetic Institute in Potsdam, Germany.

The astronomical tower then links to the Greenwich Meridian and becomes the key beginning point of Bulgaria’s triangle network. It was linked to the important astronomical locations of Poland, Romania, and Hungary between 1957 and 1958. The tower features a revolving 360° dome with an entrance through which the celestial lumine is guided by the astronomical theodolite. Because of the increased light of the night sky, the usage of the astronomy tower started to decline in the 1970s. Since 1992, it has not been utilized for astronomical observations. The tower is a cultural landmark.