Foucault's Pendulum + Solar Eclipses

Was it ever determined if solar eclipses effect changes in Foucault Pendulum rotation? I can find no definitive answer to this question despite the fact that I am pretty sure NASA had a big program to determine the answer a few years ago.

Here is an except describing the question more fully from

“The rate of rotation of Foucault’s pendulum is pretty constant at any particular location, but in 1954, during an experiment with one, a physicist named Maurice Allais got a surprise. His experiment lasted for 30 days, and one of those days happened to be the day of a total solar eclipse. Instead of rotating at the usual rate, as it did for the other 29 days, his pendulum turned through an angle of 13.5 degrees within the space of just 14 minutes. This was particularly surprising as the experiment was conducted indoors, away from the sunlight, so there should have been no way the eclipse could affect it! But in 1959, when there was another eclipse, Allais saw exactly the same effect.”

I’m sorry that I have nothing to add to the OP, but this sentence struck me as extremely silly - if an eclipse could have this effect it would certainly not be due to the amount or quality of light striking the pendulum, otherwise every time you shut the lights out in the building the pendulum would jump.

Carry on . . .

Maurice Allais is probably better known in the field of economics in which he won the Nobel prize in 1988. From the Nobel site, his autobiographical sketch on this page,, says

Further information on this phenomenon and recent efforts to reproduce Allais’s results can be found on this page,

NASA has a very detailed page about this effect and efforts to test it during an eclipse in 1999 here,

There are also a number of very interesting links (few of which I’ve had a chance to look at) on this page,

But if you follow those links they are either written before the eclipse or just after before data had been assembled. No links to publication or anything. Plenty of interest beforehand, ABC, NBC, BBC etc and a paucity of links afterword.