Variations of ΔT from historical eclipses observed at multiple sites

The rate of rotation of the Earth is slowly decreasing in time. Universal Time (UT) is a time scale based on the rotation of the Earth and ΔT is defined as the difference between the uniform time‐scale (Dynamical Time), and the Universal Time, it is clear that ΔT will vary with time, but it does not vary uniformly, because there are irregular fluctuations. It is not possible to obtain past exact values for ΔT, being the only possibility its deduction a posteriori from ancient observations, in particular from occultations and total or annular eclipses.However, the derived relative error from ΔT obtained from ancient eclipsed is quite large, mainly because of the large width of the totality zone and the inaccuracy in the definition of the observational place. These former problems may be partially solved with the analysis of eclipbse records from multiple sites, which could give a narrower parameter range.