Shortt Type Observatory Regulator No. 26

The Russians imported several Shortt clocks for use in their laboratories and observatories. After studying the Shortt free pendulum system, they decided to embark on improving it. In 1936, the Etalon factory tested the first models of the Russian clocks, which had a free and synchronized pendulum. When work was finally completed in 1952, the variation was only one millisecond per day, an astonishing improvement over the original. The Russians had used incremental design improvements to double the precision of the original Shortt. However, these clocks were virtually unknown outside of Russia until relatively recently.

This clock is very well designed and particularly robust. Much attention has been paid to detail. For example, the slave clock has a door within a door to permit access to the clock dials without opening the main door to avoid interference. No. 26 is one of only two clocks known to have a telescopic pendulum beat plate viewer. This clock was originally used at the Astronomical Observatory of the University of Lviv in the Ukraine.

The Etalon Factory produced probably fewer than thirty of these clocks, and only about half a dozen are currently known to exist.