I am asking for information/data based on direct observations not mathematical predictions, especially predictions based on harmonic solutions.

Raw data from observations are at the core of the scientific method.

In the 1960’s the Two-line element set for orbital parameters was pushing computers (depending on how fast you cranked them) to their limits.

A modern computer can compare direct orbital measurements (made at one second intervals over an entire day) with theoretical predictions and kick out the deviation in 10 seconds. This would be the direct one pass perturbation that harmonic solutions smear across time.

This also suggests that the Harmonic solution can be replaced with the far more precise single pass perturbation. Why have imprecise orbit predictions when the computing power for higher accuracy is easily available?