[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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