Is There Something Missing from the Antikythera Mechanism? Was It a Mechanical Planetarium–Positioner? Or a Luni-Solar Time Calculator Device? Reconstructing the Lost Parts of b1 Gear and Its Cover Disc

We present the observations and the results of our experience from many hours of constructing, assembling, handling, and interacting with our functional reconstruction models of the Antikythera Mechanism. The parts were constructed and the models were assembled by applying a strict Constructional Protocol for a Research Grade functional reconstruction, after a careful study of the Personal Constructional Characteristics/Design Style of the (unknown today) ancient craftsman, retracted from the mechanical parts of the Mechanism’s fragments. During the extensive use of our models, it was concluded that two important and mandatory indicators are missing from all current reconstructions of the Mechanism. The two indicators are necessary for the Antikythera Mechanism to be considered as a complete and self-contained operational time-measuring device which provided direct astronomical and calendar information without additional calculations. The two operations related to the preserved remains were located on gear b1 and its lost Cover Disc. The reconstruction of those missing parts was done according to the Constructional Protocol. The extensive analysis of the Antikythera Mechanism’s operations leads to the understanding of the Mechanism as a luni-(solar) time-measuring device, as opposed to the notion that it was a mechanical planetarium presenting the hypothesized planetary motions and positions.