The Reichenbach & Ertel Meridian Circle at the Tartu Old Observatory: Great Moments from the History of a 200 Years Old Instrument

A 200-year-old meridian circle at Tartu's Old Observatory played pivotal roles in groundbreaking astronomical and geodetic projects. The instrument, ordered in 1817/1822, enabled Friedrich Wilhelm Struve to measure the positions of 3220 stars for his seminal binary star catalogue (1827) and contributed to the UNESCO-listed Struve Geodetic Arc. Later, under Ludwig Schwarz's leadership, it facilitated zone observations despite deterioration. Beyond these contributions, the meridian circle served as a tool for timekeeping and astronomer training from 1822 to 1964. This study reconstructs its history using archival sources and primary literature, highlighting its enduring scientific significance.

Leppik, L. (2023). The Reichenbach & Ertel Meridian Circle at the Tartu Old Observatory: Great Moments from the History of a 200 Years Old Instrument. Cahiers François Viète, III-14, 171–189. https://doi.org/10.4000/cahierscfv.4040