Mechanical Moon Calendar

prusaprinters

<p><strong>#NoScrewNoGlue</strong></p><p>&nbsp;</p><p><strong>All you need to know about the Moon :</strong></p><ul><li>Moon Phases</li><li>Tilt of the Moon (Rising Moon / Waning Moon / Lunar knots)</li><li>Apogee and Perigee</li><li>Moon and Solar Eclipses</li></ul><p>&nbsp;</p><p>The mechanism is pretty complex with<strong> 10 wheels </strong>but the object stays simple - only 12 pieces. <strong>No screw, no glue or nothing else is needed.</strong></p><p>The mechanism is precise enough to stay <strong>accurate for several years</strong> (1 day delay after more than 10 years).</p><p><i>This Moon Calendar is inspired by the famous orrery of James Ferguson (1710-1776). I transformed it into a geocentric version on which I added the Moon and so it is a Moon Calendar.</i></p><p>&nbsp;</p><p><strong>What is a geocentric Moon Calendar ?&nbsp;</strong></p><p>This is a representation of the Sun-Earth-Moon system showing the Earth in the middle and the Moon and the Sun rotating around.</p><ul><li><strong>The Sun</strong> is representated at the outside of the big rotating ring and shows the date on the calendar. It is a 365 days calendar (without February 29th)</li><li><strong>The Moon</strong> is represented by the small circle. It rotates around the Earth in 29.53 days.</li><li>The orbit of the Moon is not a perfect circle but an ellipse with a <strong>perigee</strong> (closer point) and an<strong> apogee</strong> (far point).</li><li>The orbit of the Moon has a<strong> tilt </strong>(5.14°) compared to the ecliptic plan (Sun and Earth plan).</li><li>The Earth is inclinated on its axis (23°) and the North hemisphere points toward the summer solstice (June 21th).</li></ul><figure class="image"><img src="https://media.prusaprinters.org/media/prints/61470/rich_content/3d94d596-0dd7-4a05-bc53-2a520b812987/explications.png#%7B%22uuid%22%3A%229cbccef0-2e1e-4adb-82b0-2d2eb4529990%22%2C%22w%22%3A2147%2C%22h%22%3A1610%7D"></figure><p>&nbsp;</p><p><strong>How to use it ?</strong></p><p><strong>Use the drawing at the back to know the initial position</strong>. I used the last “big” solar eclipse (<strong>July 2nd 2019</strong>) as the reference position.</p><figure class="image image_resized" style="width:61.81%;"><img src="https://media.prusaprinters.org/media/prints/61470/rich_content/55988c76-ce98-4315-9d44-4e3064b955c8/img_1606.jpg#%7B%22uuid%22%3A%22890d1a81-f871-4393-893a-036bef9b213d%22%2C%22w%22%3A5152%2C%22h%22%3A3864%7D"></figure><p><strong>Rotate (anti clockwise) the large disk of the Sun</strong> until you reach the date you want.</p><p>Do no rotate too fast.</p><p>&nbsp;</p><p>&nbsp;</p><p><strong>Print Settings :</strong></p><p>Printed on MK3S</p><p>Filament tested : PLA (Filamentum/Prusament)</p><p>Nozzle 0.4mm : 0.20mm and 0.30mm tested</p><p><strong>Take care of your printing precision (use a small file to correct the defects) :</strong></p><ul><li><strong>CONCENTRIC CANONS MUST BE PERFECTLY SMOOTH INSIDE AND OUTSIDE</strong></li><li><strong>CONCENTRIC CANONS MUST BE PERFECTLY SMOOTH INSIDE AND OUTSIDE</strong></li><li><strong>CONCENTRIC CANONS MUST BE PERFECTLY SMOOTH INSIDE AND OUTSIDE</strong></li><li>Check if all teeth are correct otherwise print the wheel again</li><li>Ensure that your first layer is not larger (skirt effect)</li><li><strong>Try to correct every surface defects you noticed on the wheels</strong></li></ul><p><i>PrusaSlicer 2.3.0</i></p><p><i><strong>&nbsp;Edit - 11 jan 2022 : the individual files of R15, R18-R30, Earth and Apogee have been changed - there was a scale issue (thanks a lot “stellarwave”).</strong></i></p><p><i>“E pur si muove” - Galileo Galilei - 1633</i></p>