It is part of the UNESCO World Heritage Site Historic Centre of Saint Petersburg and Related Groups of Monuments.

By the 50th anniversary of the Observatory, they had built an astrophysical laboratory with a mechanical workshop and installed the Europe's largest refractor, (30 inch).

The observatory participated in the basic geodesic work, namely in measuring degrees of the arc of the meridian from the Danube to the Arctic Ocean (until 1851), and in triangulation of Spitsbergen in 1899–1901.

The Pulkovo Meridian, which passes through the center of the main building of the Observatory and is located at 30°19,6‘ east of Greenwich, was the point of departure for all former geographical maps of Russia.

Under dramatic circumstances, the main instruments were saved and stored safely in Leningrad, including the lens of the destroyed 30-inch refractor, and a significant part of the unique library with manuscripts and important works from the 15th to 19th century.

On February 5, 1997, nearly 1,500 of the 3,852 books were destroyed by malicious arson and the rest of the library items were damaged by flames, smoke or water.

The 65 cm Zeiss refractor was originally intended as a gift from then Chancellor of Germany Adolf Hitler to the Italian Benito Mussolini, but it was not delivered and instead was recovered by the Soviet Union.

The observatory organized many expeditions for determining differences of longitudes, observing passages of Venus and solar eclipses, and studying astroclimate.