The "Zero Point" of the Nation: Starting Point of Bulgaria's Geodetic Measurements

Amid the bustling streets and historic buildings of Sofia's city center lies a little-known yet highly symbolic landmark—the Main Astronomical Point of Bulgaria. This modest monument serves as the "origin point" of Bulgaria's geographic and surveying system, marking the birth and development of the nation's modern measurement framework. What is the "Main Astronomical Point"? Simply put, it is the starting point of Bulgaria's modern geodetic measurement system. Located in the heart of the capital, Sofia, this site represents Bulgaria's historical foundation in the field of geodesy. Historical Significance and Function: - **Year of Establishment**: Established in 1920 by the Geographic Institute of the Ministry of War. - **Core Function**: Before the advent of GPS technology, this point was a critical reference for Bulgaria's national triangulation network. Through astronomical observations, it precisely determined geographic latitude and longitude, serving as the benchmark for all map-making and land surveys. - **International Collaboration**: In the 1930s, Bulgarian scientist Vladimir Hristov collaborated with Germany's Potsdam Geodetic Institute to accurately determine the longitude of this point through synchronized observations, connecting Bulgaria's scientific research to the international stage. In the 1950s, it was also linked with the main astronomical points of Poland, Romania, and Hungary, further enhancing regional measurement accuracy. This location is often represented by a yellow astronomical tower or a historically significant landmark, reminding people of Bulgaria's contributions to the history of science. Although urban light pollution has rendered it unsuitable for rigorous astronomical observations, it remains a historical landmark in the city center, inviting visitors to reflect on Bulgaria's early scientific endeavors. The Main Astronomical Point of Bulgaria is a "small yet significant" corner of the city. It lacks grand architecture or throngs of tourists, but it embodies the cornerstone of the nation's geographic and modernized systems.