In my 2019 article – Interplanetary Alignment of Xuan Kong Flying Stars (五星連珠玄空飛星風水), which attempt to relate the theory of Flying Stars with the Great Conjunction in Astronomy.
This planetary alignment of Jupiter and Saturn take place every 19.85 years. This approx. 20 years duration has close similarities with the flying stars theory of marking out a new period. This is one reasons to believe that the changes of period in flying stars theory that originally developed; had came from observation of planetary alignment.
Taking another step further, looking at planets in the night sky (天), we know that they are not static (i.e. oscillation occurs as planets orbits around the sun), giving off vibration that it perhaps has an indirect or metaphysical influence on the earth (地) energy and human (人).
In Flying Star system, users of this system learned (or are taught) that the house chart is fixated when the house is build. Extrapolate a little… 20 years later when period 9 changes to period 1 ~ the issues can be quite a handful, because this is a major change from lower cycle to upper cycle in San Yuan system.
If so, knowing the planets moves, could we then, as users of Flying Stars Feng Shui system embrace a paradigm shift in our mental models that the Stars in the Flying Star chart is, perhaps not fixated when the property is build, and that you don’t need to tear down your roof or ceiling or even vacate the property in order to change period. Instead (perhaps) the stars automatically shift as we move from the current period into the next, then the simple take away is that we just need to know, when and how to apply.
This may probably be the key to explain why some period 6 or 7 property still enjoys prosperous Flying Star energy because the stars have shifted accordingly when the period shifted to period 8. For example, N3 facing (丁山癸向) in period 6 has a double stars at sitting (双星到山), as it move into period 7 has a double stars at facing (双星到向) and now in period 8 has a double stars at sitting (双星到山) + Star 9 (九运右弼到向首) + HeTu Combination (河图组合); the household move from wealth focus to family and well-being oriented.