Precision Regulator in Pressure Constant Tank

This very rare astronomical precision regulator, No. 36, in a pressure constant tank has a precision in the range of quartz clocks. Only a few of these instruments were built (all at the All Union Scientific Research Institute of Physicotechnical and Radiotechnical Measurements in Moscow) and all were delivered to observatories. From a mechanical standpoint, it is not possible to get an astronomical regulator more accurate.

The Fedchenko clock was the last and most accurate mechanical clock in a line extending from Riefler through Shortt to the final development in precision pendulum clocks, the Fedchenko. The Fedchenko clock was almost unknown outside of Russia due to the secrecy of the Cold War.