The 1923 establishment of Bosscha Observatory in Lembang, Indonesia, is frequently cited as the onset of ‘modern astronomy’ in Indonesia. This observatory has inspired the birth of several new generations of Indonesian astronomers as well as other observatories in Indonesia, including the Timau National Observatory which is currently under construction and in the completion stage. Double star astrometry has been one of the main programs since its founding. Nonetheless, records show that Bosscha Observatory was involved in research not only in astronomy but also in geodesy and geodynamics. This paper will discuss the participation of Bosscha Observatory in determining the most accurate longitudes of the Earth in the early days of its establishment. The World Longitude Determination of 1926 was the first global effort involving many of the world’s leading countries and institutions. It was proposed to determine the differences of longitude of many places with great accuracy. If this effort was repeated at intervals sufficiently separated in time, this might be used to test the possible change of their relative positions and possibilities as to the movement of the Earth’s crust as first hypothesized by Wegener. After a century of its existence, Bosscha Observatory looks to its future to continue its astrometry program and participate in determining a very accurate reference frame through the Very Long Baseline Interferometry (VLBI) technique in radio astronomy.