Mechanical Orrery

prusaprinters

This fully printed orrery (called “tellurium”) displays all you need to know about the Sun, the Earth and the Moon :The date (day, month and year with mechanical counter)The Moon phasesThe distance Earth-Moon (apogee and perigee)The tilt of the Moon (lunar knots)The all mechanism is driven by a crank.This object is inspired from the Ferguson orrery :https://collection.sciencemuseumgroup.org.uk/objects/co56780/orrery-planetary-model-by-james-ferguson-1755-1756-demonstration-models-orreries-planetaria-modelsEdit :October 14th 2022 : I updated the "crank handle". It's now easier to print and there no risk to break the clip.October 10th 2022 : fixed the missing hole in the “Earth South” to clip it - thanks to JamkasOctober 7th 2022 : fixed the flying ball foating at the top of the “counter cap” - thanks to RaymondPrint settings :Printed on MK3S - PrusaSlicer 2.5Nozzle : 0.4mmFilament : PLALow temperature (~190°) to avoid threadingPlate 1 (Support) : Z resolution 0.3mm - Color change at 1.70mm and 3.20mmPlate 2 (Turntable) : Z resolution 0.3mm - Color change at 1.40mmPlate 3 (Gears and Earth) : Z resolution 0.2mmPlate 4 (Moon and rings) : Z resolution 0.2mmPlate 5 (Sun, legs and crank) : Z resolution 0.3mmFilaments : Galaxy Black (Prusament) / Galaxy Silver (Prusament) / Gold Happens (Filamentum) I added Gcodes for the time evaluation, you should generate your own. Instructions :1- Start by gluing the 3 studs on the support then glue the legs. These are the only parts you will need to glue. 2- Take the 7 gears you will need for the mechanism (Wheels 20, 37, 39, 39L, 44, 50-19, 50-25). Make a pile with the 4 concentric wheels (20, 37, 39, 44). 3- Put the 3 wheels on the turntable (pay attention to up and down) and then insert the pile of 4 gears. 4- Take the support and use the central pillar to fit in the turntable. 5- Clip the earth ring into its support. 6- Clip the Sun, the Moon, the apogee ring, the tilt ring and the Earth support. Make sure there is a space between each platform 7- You will need to slightly pull on the pillar to insert the first wheel of the year counter. Then put the small wheel and the second counter wheel. Carefully add the cap to maintain the wheels. 8- Clip the crank handle in the crank. Then put the crank wheel and insert the crank. 9- Clip the two parts of the Earth (use the “earth clip”). Finally insert the Earth. Start with the top axis. How to calibrate the tellurium :This is an example made in October 2022 for Dinan (France). Use this kind of website to do it where and when you want :https://www.timeanddate.com/moon/@3021357?month=9&year=2022 1 - Go to June 21st, hold the crank and align the Earth ring with the Sun, the north hemisphere pointing toward the Sun (summer solstice).2. Go to September 10th, hold the crank and spin the Moon to the full moon (behind the Earth). Make sure this setting is correct by going back about 1 month, then go to September 10th again and check if it's a full moon. If not, make the correction and check again.3. Go to September 18th, hold the crank and align the top point of the Tilt ring with the Moon (highest moon angle).4. Go to September 19th, hold the crank and align the longer part of the Apogee Ring with the Moon (farthest moon).Your tellurium is calibrated.When you want to go on a previous date, go back one more month, then rotate to the desired date. You must do this to annihilate the free movements of the gears. Precision of the tellurium :Moon revolution (lunar synodic month) : Calculated : 365,256 / (47/19 x 50/25 x 50/20) = 29,5313 daysReal : 29.5306 daysTilt Revolution (draconitic cycle) :Calculated : 1 / (39/37 - 1) = 18,5 yearsReal : 18,6 yearsApogee Revolution (lunar precession):Calculated : 1 / (1 - 39/44) = 8,80 yearsReal : 8.85 years