[time-nuts] Rb-Thunderbolt test during a solar eclipse
iovane at inwind.it
iovane at inwind.it
Mon Sep 3 19:16:10 UTC 2012
Dear time-nuts,
a friend of mine, Prof. Alexander Pugach (1), did an experiment on January 15,
2010, comparing a Rb standard to a GPSDO during a solar eclipse. The
experimenal site was Kiev, Ukraine.
With reference to the attached graph, his text is (note: the red curve belongs
to another test; the curve which matters here is the bold blue one):
****************************
Dear colleagues,
An experiment has been made aiming to investigate, how the “daily rate of
clock” varies during a solar eclipse on 01.15.2010.
In our observatory the high-precision rubidic standard (RbSt) of frequency is
exploited. Its indications were compared to a basic frequency from highly
stable GPS receiver TRIMBLE Thunderbolt Е. The difference obtained is noted as
“residue” and expressed in nanoseconds (ns).
This residue was conventially set equal to 0 ns at 00h 00m 13.01.2010. The
mean “daily rate of RbSt” equals 2740 ns/d, i.e. 3.17 10-11. In the Figure
this rate is shown with blue dashed line. What we have really registered is
shown with the bold blue curve.
The main minimum of this difference approximately coincided with the eclipse
start on the Earth. The derivative on site А-В is approximately 6 times as
much as mean “daily rate of RbSt”.
............
19.02.2010
****************************
Apparently, the difference of rate of the two clocks varied by some 4000 ns, A
to B, in the 6 hours of duration of the eclipse (s to e = start to end of
eclipse at earth, T1-T4 =eclipse in Kiev).
I would ask you time-nuts, if such a variation could be simply due to an
occasional sum of "ordinary" adverse factors such as temperature, holdover, sky
view, multipath, etc.., or it is really too large to be explained that way.
Sorry, I've no idea of what would be the worst case for any of the above
factors.
Thanks,
Antonio I8IOV
(1) Prof. Pugach is a senior astronomer at the Academy of Sciences of Ukraine.
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