Tbilisi Observatory, Astronomical observatory in Tbilisi, Georgia

Tbilisi Observatory is a former geophysical observatory on Davit Aghmashenebeli Avenue in the Kuki district. Its main building, completed in 1861 to a design associated with astronomer Arnold Moritz, has a central rotating wooden tower and wings spread around it. A deep moat once encircled the structure, crossed by a wooden bridge later replaced in stone. Today the building houses the Museum of Geophysical Sciences of the Georgian Academy of Sciences.

Founded in 1837 as the Tiflis magnetic-meteorological observatory on Sololaki ridge, it moved several times: to the foot of Mtatsminda (1844–1851), to Avlabari (1851–1861), and in 1861 to a purpose-built site on Kuki. In 1865 it became the Main Caucasian Observatory with physical and astronomical sections, and in 1867 the Tiflis Physical Observatory. A seismic station opened in 1899, and in 1900 it issued the Russian Empire's first seismic bulletin.

The observatory's name changed with the city: it was the Tiflis Physical Observatory from 1867 and became the Tbilisi Geophysical Observatory in 1926. Its magnetic station, moved to Dusheti in 1935, still gives the observatory code "Dusheti", while the Minor Planet Center lists it as code 125, "Tbilisi".

The observatory stands at 403 m on Davit Aghmashenebeli Avenue in the Kuki district, on the site of the 1861 main building; only that building, a small structure southeast of it and an altered dwelling survive. The Geophysical Sciences Museum of the Georgian Academy of Sciences now occupies the building, so check its opening before travelling. A deep ditch once ringed the main building, crossed by a wooden bridge later replaced in stone.

The observatory's main building, completed in 1861 on what is now Davit Aghmashenebeli Avenue, was surrounded by a deep moat cut down to bedrock and filled with water to block traffic and vibration from the adjacent highway. A wooden bridge, later replaced by a stone one, crossed its northern side.