The pendulum clock in Trinity College, Cambridge was installed in 1910. It is remarkably accurate, known to be better than one second per month. In 2009 a system was installed to monitor the "going". The work was done as part of a 4th year MEng project at the Engineering Department. A sensor on the pendulum detects the going of the clock, which is compared to the accurate time signal from a GPS receiver.
Here is a graph for the last 30 days of drift (updated every 3 hours):
For an entirely mechanical clock the accuracy is remarkable.
A barometric compensator was installed at clock change - midnight 28 March 2010.
The clock is regulated as infrequently as possible so as to stay within +/- 5 seconds of the correct time. This enables the steady-state physics of the clock to be examined without unnecessary interference.
The black dots ● indicate that there is a comment relating to the time indicated. Blue arrows pointing down ▼ indicate that an adjustment was made to the Going of the clock by removing weights from the pendulum. Red arrows up ▲ indicate addition of weights to speed the clock up.
- 20 Jul 2014 [12:00]
- top-up wind with newly-doctored Stephanie Hill and Simon Jones. Off to Bath.
- 20 Jul 2014 [11:56]
- the wear patterns on the quarters strike plate are looking normal [link] . Perhaps just filing it down and greasing it is all that was needed.
- 17 Jul 2014 [11:00]
- visit to the clock by TC computer office guys Andrew Cullen and George Townsend, with Rick Lupton showing them how the web-based monitoring system works. They also did a top-up wind.
- 16 Jul 2014 [11:00]
- Great to have Graham Newman helping with the clock - fixing the Quarters anomaly: from time to time the quarters will skip and the quarter-past does an hour, the half-past does quarter-past etc. Why? A real mystery. [link]
- 12 Jul 2014 [11:00]
- top-up wind with Malcolm Good. Investigating the Quarters mystery: why does the clock occasionally miss striking quarters?
- 11 Jul 2014 [00:33]
- winding after the Geoengineering debate for Cambridge Summer School: Matt Watson (no winding) @matthew__watson, Malcolm Good, Terje Doeviken, @giovannibisutti, isobel smith, Alanna Punch, Katharina Tomaschek who used the last key!
- 06 Jul 2014 [12:06]
- winding after a boozy Annual Gathering (well done!) by Miss Li Yan, Dr Richard Manns
- 29 Jun 2014 [00:05]
- winding: Beatrice Hunt, Matthew Dougherty, Harriet Kilduff @littlehduff, Hannah Kilduff @hannahkilduff, Louise Dorignon @therightscale
- 27 Jun 2014 [10:23]
- winding with Dan Safka @Rubicycling