[time-nuts] GPS disciplined mechanical clocks
Magnus Danielson
magnus at rubidium.dyndns.org
Thu Mar 5 19:56:13 UTC 2009
Tom Van Baak skrev:
>> In the evolution of timekeepers the SHORTT CLOCK was one of the great
>> milestones.
> ...
>> These clock kept very good time.
>> Cheers, Neville Michie
>
> Yes, stability at 1 day was right around 1e-8 for a Shortt.
>
> Stability (ADEV) of one Shortt pendulum clock:
> http://www.leapsecond.com/museum/shortt/
The traditional masterclock for those devices which is found on
http://www.leapsecond.com/museum/earth/
is a bit more complicated. The referenced frequency (of period 86400 s)
is not the actual frequency but rather the SSB beat frequency of the
free space rotation frequency and the rotation speed around the heat
radiator some 8 ligth minutes away. The rotation period is about
86,164090 ks or 11,605762 uHz (and not mHz incorrectly noted on the
page). The rotation around the heater has a frequency of about
31,6887385 nHz.
Cheers,
Magnus
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