In brief:
The most remarkable phenomenon in my pendulum is the periodic change in rotational direction of the elliptical path, and the fact that these changes seem to take place at the N-S and E-W transitions of the foucault plane.
The experiments here show that the periodicity is a quite persistent phenomenon. After kicking the ellipse to the other direction it restores with a time constant of rougly one hour. What can this tell us?
Fig. 1 Animaton of screenshots form the compass display, taken at intervals of 5 minutes and covering one complete Foucaut Rotation.
The display is aligned with the compass directions at my location
We see a number of position measurements (blips) from the Hall detector system.
Light-blue: HalfPeriod-1, white: HalfPeriod-2, Red circle FP plane orientation.
Green blip: first sample after a CenterPass.
Red blip: like green blip, after rotation to horizontal laying ellipse.
The rotational direction of the ellipse is from the green blip into the light-blue blips.
So we have CW direction in quadrants 1 and 3, and CCW in quadrants 2 and 4.
Fig. 2 Time display. Vertical scale 45 px / div.
Yellow: Time of the day in steps of 1 hour.
Light blue: Precession angle. Scale +180 .. - 180 deg, center = E-W crossing.
White: Ellipse minor axis. Amplitude ca. 30 mm. + = CCW, - = CW.
The ellipse changes direction at precisely the N-S and E-W transitions.
The period of the precession angle is very close to the theoretical 30.4 hr for my lattitude (NL).
Zero crossings are at 02:01 and 08:28 giving 30:24 interval.
Data source: 2024-08-04.log to 2024-08-06.log.
Fig. 1 is from the same data, North to North, 2024-08-04-18:10:01 to 2024-08-06-00:40:53.
Fig .3
Here I have manually kicked the bob to the opposite rotational direction of the ellipse.
It restores with a time constant of roughly one hour. Has anyone an idea where this time constant may come from?
The zero crossings of the FP are at 11:37, 03:31 and 18:58, giving intervals of 15:54 and 15:27, summed: 31:21.
Data source 2024-7-28.log, 2024-07-29.log