The Draconic gearing of the Antikythera Mechanism: Assembling the Fragment D, its role and operation

The unplaced Fragment D of the Antikythera Mechanism with an unknown operation was a mystery since the beginning of its discovery. The gear r1, which was detected on the Fragment radiographies by C. Karakalos, is preserved in excellent contdition, but this was not enough to correlate it to the existing gear trainings of the Mechanism. After the analysis of AMRP tomographies of Fragment D and its mechanical characteritics revealed that it could be a part of the Draconic gearing. Although the Draconic cycle wa well known during the Mechanisms era as represents the fourth Lunar cycle, it seems that it is missing from the Antikythera Mechanism. The study of Fragment D was supported by the bronze reconstruction of the Draconic gearing by the authors. The adaptation of the Draconic gearing on the Antikythera Mechanism improves its functionality and gives answers on several questions.