Reconstructing the lost eclipse events of the Saros spiral applying the Draconic gearing on the Antikythera Mechanism. The impact of the gearing errors on the pointers position

TL;DR

This study reconstructs lost eclipse events of the Antikythera Mechanism by applying assumed Draconic gearing, analyzing gear errors, and assessing their impact on eclipse prediction accuracy.

Contribution

It introduces a software-based reconstruction method for lost eclipse events using the Draconic gearing assumption and evaluates gear errors' effects on the mechanism's predictions.

Findings

Reconstructed previously lost eclipse events.

Identified gear eccentricity errors affecting predictions.

Demonstrated the impact of gear errors on pointer accuracy.

Abstract

We present new observations concerning the procedure for the reconstruction of the lost eclipse events engraved in the Saros spiral cells of the Antikythera Mechanism. For the reconstructed eclipse events we applied the assumed, albeit missing, Draconic gearing of the Antikythera Mechanism, which was probably a part of the Mechanism gearing, representing the fourth lunar motion, the Draconic cycle. The Draconic gearing is very critical for the eclipse prediction and defines whether an eclipse will occur. For our research we created a program which presents the phase of the four lunar cycles and the position of the Draconic pointer relative to the ecliptic limits. After calibrating the software according to the preserved eclipse events, the lost eclipse events of the Saros spiral were calculated and discussed. The procedure for the calculation of the events times by using solely the Mechanism is also presented. The eccentricity error of a gear which is preserved on the ancient prototype is discussed. An experimental setup facilitated the analysis of the mechanical characteristics of gears with triangular teeth and the errors. The experimental study of the gears errors revealed the strong impact the Antikythera Mechanism pointers have on the results.