The influence of Hipparchus in Antikythera mechanism

Abstract

Abstract Around 1900, a group of sponge divers, pulled out from an ancient Roman shipwreck, near the Antikythera island, a piece of a hardly distinguishable geared mechanism which is known since then as “The Antikythera mechanism”. Until now the exact use of some of its survived gears is investigated and there are speculations about its missing parts. In 2005 two revolutionary technical methods were applied on Antikythera mechanism. The first is known as : (3D) X-ray computed tomography (CT) by X-Tek Systems Ltd, with the use of which many hidden details under the corrosion, came to light. The second is known as : Polynomial Texture Mapping (PTM) which was applied by HP Labs, revealing engraved symbols and letters on Antikythera mechanism surfaces. After all these years of research, a more comprehensive picture of this machinery was built, leading to the conclusion that it was used as a multi functional “astronomical calculator” according to Freeth et\xa0al. (2006b) with many impressive capabilities such as: • a prediction of upcoming Solar and Lunar eclipses • a calculator of the four astronomical cycles (Metonic cycle, Callippic cycle, Saros cycle, Exeligmos cycle) • moon phases indication • Sun and Moon position in zodiac The whole mechanical construction seemed covered by a wooden case with a front and a back door with engraved inscriptions on them. According to Freeth\xa0et\xa0al.\xa0(2006b) “The inscriptions support suggestions of mechanical display of planetary positions” proving the existence of a missing planetary subsystem. In this decrypted text, according to Freeth\xa0et\xa0al.\xa0(2006b) , astronomical terms have been recognized like stations like statio,conjunctions and according to Jones\xa0(2017) , there are references about the names of the five known planets. Researchers are trying for years to present planetary activity on their models suggesting different solutions with a common characteristic. In all models of planetary motion, the epicyclic theory is applied. Although this theory is precise enough for planets with negligible eccentricity, fails to demonstrate the real recorded apparent orbit of planets with significant eccentricity, like Mercury’s which is 0.205. On the other hand in Antikythera mechanism remains, there is an advanced device, known as the “pin & slot”, which simulates the non-uniform motion of the moon. According to Moussas\xa0(2009) ...The difference between Kepler’s predictions on the angular velocity of the Moon during the month and the mechanism’s prediction is of the order 1/400 .... So if the constructor used a specialized gearing to model the moon’s orbit eccentricity which is 0.0549 why not do the same for Mercury’s case with an eccentricity of 3.7 times bigger? Many speculations about the Antikythera mechanism’s purpose have already been expressed, but nevertheless, accuracy is its undeniable feature which should be reflected in the mechanism’s astronomical indications. So, there’s a question that might be answered. ”Is it possible, the planets eccentricity can be simulated using the pin & slot device?”. This research tries to find an answer and proposes a feasible epicyclic gearing which can simulate the geocentric apparent path of Mercury. The construction is taking seriously the planet’s eccentricity, trying to minimize the discrepancy between expected and indicated measurements. Our proposal is based on theories known at the time Antikythera mechanism was constructed.