[time-nuts] The Pendulum Paradigm by Martin Beech, 2014

[Jim Lux]

On 10/28/15 7:48 PM, Jim Lux wrote:
> On 10/28/15 7:23 AM, Peter Reilley wrote:
>> I have been pondering pendulum clocks.   I was wondering what the ADEV
>> of a
>> pendulum would show.   I assume that you could see the errors in the
>> gear train.
>> You should see the period of each gear.   You should see the spring wind
>> down
>> and being rewound.
>>
>> Further, would you be able to see the phase of the moon and the tides?
>> This
>> is using the pendulum as a gravimeter.   Would it be sensitive enough
>> for that?
>>
>
> yes.. it's in the sub-ppm range, as I recall.
>
> Period goes as sqrt(L/g)
>
>
> from wikipedia
> lunar tidal acceleration at the Earth's surface along the Moon-Earth
> axis is about 1.1 × 10−7 g, while the solar tidal acceleration at the
> Earth's surface along the Sun-Earth axis is about 0.52 × 10−7 g
>
>
> So sqrt(1/(1+1E-7))... about 0.05 ppm
>

so you'd need an ADEV <1E-9 at a tau of 12 hours


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