Menu Close

Synchronome Secondary Clock


This is a round wall-mounted clock with three dials. The large dial indicates seconds. Two smaller dials indicate the hour and the minute. A thick layer of glass with a beveled edge covers the clock-face. This is held in place by a metal rim. This in turn is mounted in a wooden surround.

The back cover of the clock is missing. Green felt is around the rim of the missing back, to cushion the back. There are four rotating metal latches that would have held the back of the clock in place.

Inside the clock, some large clockwork gears are visible, alongside a copper coil and two wires that go through holes in the rim of the clock. These have been cut off just outside the rim.

Accession Number: 2018.ast.105

Alternative Name: Synchronome

Primary Materials: Metal: Iron Alloy, Glass, Wood


On the face of the clock: “SYNCHRONOME LONDON”

Stamped into the brass of the clockwork mechanism: “ENGLISH MADE

Dimensions (cm): Diameter = 38, Height = 8


This clock is used for accurate, synchronized timing to the second, likely in an astronomical context. This secondary or “slave” clock is powered by and can be synchronized via an electrical circuit from a primary or “master” clock driven by a pendulum.


Very Good: The interior and face of the clock are in excellent condition. The reverse of the clock is missing the cover for the clockwork gears. Green felt that was used to cushion this cover is badly damaged, possibly by insects. The wooden surround of the clock is warped in places causing joins to be slightly wider than presumably intended. On the left side of the rear there is a rough hole in the wood, as if made by a drill. The back of the clock is marked and scratched across its service, including an unreadable word written in pencil (possibly “Bacie”).

Associated Instruments: 2019.ast.251

Manufacturer: Synchronome Co. Ltd., London

Date of Manufacture: Mid-20th Century


This object was likely used at the David Dunlap Observatory as one of a number of secondary clocks driven by a central Synchronome clock in order to synchronize observation timing across the observatory. It was moved from the David Dunlap Observatory in Richmond Hill in 2009, upon the sale of the observatory. It was stored at the Department of Astronomy and Astrophysics until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.

Additional Information and References:

There is a similar clock dating from 1920 in the collection of the <a href=””>National Maritime Museum, Greenwich, London.</a> This one was used at the Royal Observatory.

Historical Notes: