Personally I go with the Nature article. The other papers look like they
are anomaly hunting because they have a known event.

Having said that, we have two H masers at our observatory in Hobart and we
have a system set up to measure their phase difference down to about 0.03
ns. I will report back any anomaly.

We, of course, are not in the path of the eclipse, however gravitationally
there is still an alignment. Just through the Earth.

Jim Palfreyman

On 29 May 2017 at 08:17, iovane--- via time-nuts time-nuts@febo.com wrote:

The effect you're looking for depends on a comparison of two different
kinds of atomic clocks eg Cs vs H-maser so the maser comparison presumably
will be a null measurement.

But I see the path of totality passes a bit north of NIST Boulder and I'm
pretty sure they will notice if there is an effect ! ( I'm highly sceptical
there is one. Searches for exotic physics over the last three decades have
consistently turned up nothing. I did it myself at the beginning of my
career with the "fifth force", a composition-dependent, short range
gravity-like force. The positive results all turned out to have very subtle
classical physics explanations)

Cheers
Michael

On Mon, 29 May 2017 at 9:35 am, Jim Palfreyman jim77742@gmail.com wrote:

In message CAGP4rdnJXgFWgQuBokFdUgeC90-DP2A2cNSdwypx8vS_bTBFhg@mail.gmail.com
, Michael Wouters writes:

It would have to be between clocks where the clock-atoms have very
different masses (for instance Cs vs. H) but it would also have to
be clocks where the clock-photons have very different energy.

So the best setup would be H-maser Cs or Rb foundtain and an trapped
ion optical clock.

Since any physicists at NIST will be keenly aware of the Nobel
Prize dangling in front of any competently measured effect, I think
we can trust them to be on the ball :-)

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

Apologies, I didn't read the paper carefully enough. The original claim
does appear to be for a comparison of like clocks eg Cs vs Cs, with a claim
of greater effects for a comparison of clocks in and out of the eclipse
path.

Cheers
Michael

On Mon, 29 May 2017 at 8:20 am, iovane--- via time-nuts time-nuts@febo.com
wrote:

Hi,

On 05/29/2017 09:56 AM, Poul-Henning Kamp wrote:

Somewhat south of NIST Boulder is the USNO backup clock at Shriever
Airforce base, just next to the GPS Master Clock. USNO has rubidium
fountains and hydrogen masers there, and some cesiums. If there would be
any significant effect, I'm sure USNO would also look at it, and also
compare to its Washington DC set of clocks.

Honestly, I'm sceptical that there is very much going on there. We have
three orbital masses that will almost align, but they almost align on a
regular basis, it's just that the shadow of the moon just don't hit the
earth very often. The graviational pull of moon, sun and earth keeps
adding continuously so we should already be able to measure these
individual effects separately and not only when it happens to occur at
the same time.

What we can expect is the effect of the shadow, which can potentially
affect the ionspheric TEC delay and for that matter temperature of
troposphere and thus delay there, and that way cause our measurements to
get skewed. This has however nothing to do with the clocks itself.

Humans is a bit too occupied by alignment in the sky. While a nice show,
I'm not to impressed about its scientific significance in this case.
There is things to learn from most perturbations sure, but as always,
some reasoning to sort out what we could expect is always good.

Cheers,
Magnus

To my mind there may be some effect due to small variations in gravity. The Chinese paper is very interesting and does propose classical explanations for the observed gravimeter anomalies. Even so , the variations that were detected by them should be detectable with a sufficiently stable clock. However as the reported anomalies are only 6-7 micro-gal which, using a quick interpolation of the units wikipedia article data, is roughly equivalent to an altitude variation of 2-3cm.  That would probably be undetectable with anything less than an ion clock.

"The power of accurate observation is commonly called cynicism by those who have not got it. »
George Bernard Shaw

During regular night/day cycles I can just barely observe the night-day
shift in WWV propagation from Colorado to my location near Washington DC,
using the NTP WWV audio refclock. It amounts to a few hundred microseconds
of shift. I last touched that code about 15 years ago.

Now that I have a 10MHz GPS OCXO (well, I've had that for about 15 years
too, getting that was the reason I stopped dinking with the WWV audio
refclock) I wonder if there's some simple hardware I could build that would
let me do superior carrier-phase type measurements on WWV propagation. If I
could see the night-day shift more clearly then I might see an ionospheric
effect during the upcoming August 21 eclipse, which nicely traces a path
from west to east not too far off the line between Ft Collins and my
location.

Tim N3QE

On Sun, May 28, 2017 at 6:17 PM, iovane--- via time-nuts <time-nuts@febo.com

In message CAJ_qRvYfe2egbZVBzahyct5o7z3FUFkApEPE=uYM01Gfc+QHDA@mail.gmail.com
, Tim Shoppa writes:

The Kiwi-SDR is one option.

Slightly more hardcore is to attach a 1Ms/s ADC to your antenna and
a computer and clock it from your house-standard.

See:
http://phk.freebsd.dk/loran-c/

Specifically:

http://phk.freebsd.dk/loran-c/CW/

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.