iov...@inwind.it wrote:
Time-nuts,
many of you are routinely recording - or may easily do it - the
trace
of the control voltage of non-free-running crystal oscillators
(disciplined by atomic resonance or GPS).
Once again I'm here asking you to
keep an open eye during a solar
eclipse, which will occur on January 15.
For meaningfull measurement shall the temperature shall be logged as well.
My current opinion is that the eclipse couldn't affect atomic
resonances at a
measurable level for the state of the art, but could
affect massive (as
compared to atoms) pieces of vibrating matter.
Well, it has been established that they do affect atomic clocks onboard
GPS satellites and that this can be correlated to the clocks temperature
dependencies. Improved temperature compensations on modern rubidiums
flown has reduced this efffect to the best of my knowledge. Rubidiums
have a temperature dependence due to their traditional design, but this
can be reduced by design and by compensation.
The control voltage trace tells us whether a crystal deviated, even in
front of a constant rate of the whole clock.
I recall (already mentioned in this list) that previous tests
(Max Plank Institute) showed no deviations of atomic resonances, but we
don't have info about control voltages, and that S.W.Zhou instead
claimed to have observed deviations that indeed I believe were
deviations of crystals not promptly steered.
Tossing the same clock into a climate chamber and test the temperature
dependence would be interesting.
During this eclipse a numerous team of researchers will be conducting
sophisticated pendulum tests at the Maldives (latitude near to zero,
no Foucault effect), and a number of US institutions, located in the
anti-eclipse path, will provide gravimeter data. Elsewhere, Russia and
Florida at least, torsion balance tests will be conducted. Just to
mention what I'm aware of.
As far as I know, nobody will provide clock (I would say oscillator)
data. Hence I' m asking this list to give a contribution.
Make sure to separate temperature effects from that of any other effect,
such as gravitational.
What I ask is to send me your control voltage data, possibly for the
days 14-15-16 January, and from preferred locations -but not only- in
the eclipse or anti-eclipse path, even penumbra or anti-penumbra.
T-bolt and Z-3801 owners with the correct software should be able to
deliver suitable data.
Cheers,
Magnus
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