I have some questions involving precision clocks and the information that can be gained from "reading" them. I hope this is the correct place on this site for the question but if not a redirect would be greatly appreciated. This post may be a bit long winded, but I want to explain my position before simply introducing the questions so you can see why my train of thought is where it is at now. I have been reading up on the achievable accuracy of pendulum clocks specifically the Shortt-Synchronome and "Clock B" in the Royal Observatory and it really is impressive the level of accuracy these clocks have achieved for being subject to the laundry list of environmental variables, especially considering how long ago they were created (at least theoretically with Harrisons design). I have read through many articles stating that the Shortt clock was the first pendulum clock operating more accurately than the earth itself as a regulator, allowing us to observe variations in the Earths rotation (1924-1927 Admiral Fountaine personal observatory) which was confirmed shortly afterwards by the Greenwich Observatory in 1927. Although the International Journal of Science "Nature" published a paper by J. Jackson and W. Bowyer in June 1928 that closes with the statement below countering that claim? "It appears that the principle of their constructions is such that they could be used to check the uniformity of the earth’s rotation if only material stable for several years to 1 part in 100 millions could be obtained for the manufacture of the pendulums…..a run of a few years would possibly suffice for errors of 1 second to accumulate in the earth’s rotation, but a variation of 1 percent in the growth of the pendulums would introduce greater irregularity in the clock error. It appears impossible to be certain that any piece of material has the required degree of stability, and until pendulums of different materials in different parts of the earth agree in supporting the motion of the moon and planets against the earth’s rotation, clocks will not play an important part in checking the uniformity of the earth’s rotation." In the book "My Own Right Time", Mr Woodward explains his application process' for obtaining specific information(data) from "noisy" samples from clocks. He is very mathematical and precise with his explanations and lists the supportive information, giving insightful examples to what was learned along the way and how it is applied in the field. Similar Articles can be found online regarding the two clocks I listed above with detailed charts showing changes in temperature, barometric pressure, humidity, ect. I have even found documents showing the ability of these and other precision regulators to show the differences in local gravity at different locations on the earth! BUT their is one subject I can't seem to find covered in any of these, PRECESSION! The physics and mathematics supporting the operating principles of a Foucault Pendulum are well documented, as are examples of its mechanical inception and operation backing up the Data. In short, we know that the rotation of the earth can be expressed through a pendulum who's design has been optimized to allow this behavior however I can't seem to find any scientific publications that elaborate on the Q of a system like this. This leads to my Questions. Has anyone observed the effects of Earth's rotation on a precision Regulator incorporating the clocks latitudinal location on Earth? Has anyone analysed detailed charts of a clocks performance with comparisons to the above sources of noise supporting a new, previously undocumented form of noise? If I understand these subjects correctly.... A precision regulator should experience measurable increased friction through rotational torque applied to the suspension of the pendulum. The pendulum is operating in a linear plane in space while the earth and clock holding the pendulum are moving underneath its nose. I understand the force may be quite small and express itself over a long period of time, But if a Foucault Pendulum can be designed and optimized to express this force, we know its role on physical pendulums is present and measurable. Is it really possible we can detect local gravitational differences as well as the nutation of the Earths rotation with a simple pendulum, but the rotation of Earth in space has no measurable effect on the clock?? When I consider the way this effect would apply itself, it becomes more frustrating to think it has not been observed before especially in a knife-edge suspension. I feel that the elasticity of a spring suspension may "absorb" these forces, but a knife edge must surely feel a change in its operating friction? Is the force so small that the general "damping forces" present in a precision regulator completely overshadow it? Or is the Q of a Foucault pendulum high enough that only then this behavior is observable? I would love to hear any thoughts or opinions on the subject!