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26 Mar 2018 [16:00]
a few tweaks, with John Aldridge: 1. stop pendulum to lower the prism by a couple of mm to make sure that the twist laser clears the clock-bed beam; 2. cleaned the prism (a fingerprint was causing a big diagonal difraction streak); 3. replace the laser screen with a 1mm polythene sheet; 4. calibrated the tilt level (found that it was pretty good, 1mV/mrad and that the zero-offset knob doesn't introduce scaling errors); 5. restart pendulum and check going, no regulation required.

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Interval between data points: seconds [either 3 seconds (weather data is duplicated) or multiples of 60 seconds (all data is averaged)].

[Raw data: Clock | Weather]

Contact:, Trinity College, Cambridge