講演情報
[PO2-14]Optimization of Gear Systems in Mechanical Planetariums Aimed at Realistic Reproduction of Planetary Motion
*Risa Yoshida1, Kurara Tsutsumi1 (1. Kobe College High School (Japan))
キーワード：
Mechanical planetarium、Planet projection、Planet cage、Gear、3D printer
Our research aims to create a mechanical planetarium that accurately reproduces the apparent motion of planets.Since the introduction of the mechanical planetarium in 1923, this technology has been in continuous operation for over a century. In recent years, however, digital planetariums have gradually become the dominant form because they are easier to operate and more compact than their mechanical systems. Though, it is difficult to understand how planetary motion is generated. Planet projection in mechanical planetariums is achieved through a device known as the planet cage. This mechanism reproduces the orbital periods of the Earth and other planets by combining multiple gears with differing numbers of teeth. By adjusting the rotational speed of each gear, the planet cage mechanically simulates the orbital motion of the planets' apparent movements onto the dome. Using the existing mechanical planetarium, the Minolta Camera Co., Ltd. “Minolta Planetarium MS-10” (as MS10), we investigated how planets are projected. We also manually counted the number of teeth on the gears used in the MS10. Based on this, we investigated the optimal gear tooth combinations to achieve high-precision planetary projection. Specifically, we defined the orbital period based on the angular displacement of each planet over 1000 years and set this as the target value. Then, we comprehensively searched for the optimal tooth count combination. This enabled highly accurate reproduction of planetary projection in mechanical planetariums. Furthermore, based on the obtained tooth count data, we constructed some prototypes, and clarified problems. The orbital velocity is not always constant. This study has not yet been able to reproduce the variations within the orbital period caused by elliptical orbits. Moving forward, we will work on reproducing elliptical orbits and aim to complete a high-precision mechanical planetary shelf manufactured using a 3D printer.