The beginnings of the Borowa Góra Geodetic and Geophysical Observatory date back to 1929. One of the intersection points of the latitudinal and longitudinal chains of the then assumed triangulation, located in the area of today’s Observatory, was adopted as the central astronomical point for the new measurement of the country.
The first determination of the difference in astronomical length between the Borowa Góra Observatory and the Astronomical Observatory in Paris was made in 1929 by Dr. Antoni Czeczot from the Ministry of Public Works and Dr. Jan Krassowski from the Military Geographical Institute with newly purchased transitional instruments from Askania Werke. In 1930, the astronomical latitude of the point and the astronomical azimuth of Borowa Góra – Modlin were determined.
Source: http://www.igik.edu.pl/pl/bg-rys