[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
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.


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