Astronomical dating agency
There is much discussion of accuracy and more of eclipses.
The only solid facts must surely come from verifying planet observation and then tracking those dates and comparing them to those given by the ancients. As you have found astronomical observations can indeed be used to help provide support for chronologies of the ancient world, no method is perfect however and there are problems with this.
Even the solar wind is not powerful enough to affect materially the movements of the largest observable objects.
If one can predict the movement of any object, then one can back-track that object.
Better yet, one can determine within a very narrow tolerance where a given object was in the sky, and how long ago a spectacular coincidence event (such as an eclipse of the sun or moon) occurred.
The random wind and water currents that affect the movement of objects on the earth are absent in outer space.
The International Astronomical Union (IAU) was founded in 1919.
Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation.
All astronomical observations one can make related to the Solar system contain many layers of cycles.
Everything of course varies on the cycle of a year as the Earth orbits the Sun, however due to the motion of other bodies and slow periodic changes in Earth's orbit there are also longer period cycles.
An additional problem is that in early history (and even comparatively recently) the calendars were not constant.