Eclipse Metacycles is an interactive art installation where spinning tops control time in a simulated solar system. When you spin a top, the sun, earth, and moon move through their orbits.
Turn the top slowly and you can move through days and weeks, isolating individual eclipses. Spin the top quickly and repeating patterns of eclipses over decades and centuries emerge.
The spinning tops are the perfect metaphor for the orbits of planets and moons. Rotate the top clockwise and the moon proceeds forwards. Rotate it counter-clockwise and it reverses direction—time goes backwards!
The projection offers three different views of the solar system. A side view helps find the moments where the sun, earth, and moon are all aligned and an eclipse can occur. A top-down view with a fading afterimage emphasizes the spirograph movement of the moon as it orbits the earth.
A third view draws hundreds of years of eclipses in horizontal lines across the screen, revealing long-term patterns.
Eclipse Metacycles Video #
Technical Details #
The tops carry an accelerometer which gives an indication of how quickly it’s spinning. The breakout board has an orientation sensor as well, but I didn’t end up reading from it.
The accelerometer data is picked up by a Teensy board which sends the readings wirelessly to the laptop using an XBee module.
The laptop runs a Processing sketch which uses the readings to control a simulation of a mini solar system. The motion of the top is translated into a time delta which moves the simulation forward or backward, depending on the direction of spin.
The Processing sketch also listens for button presses from a wireless mouse I used to (covertly) switch between different visualizations.
The simulated solar system had to be tailored to give the best learning experience. It’s very unrealistic in terms of the distance between the sun, earth, and moon and the path of their orbits. However, eclipses occur far more often and are much easier to see, allowing guests to develop insights from the interaction.
Making Of #
The project took several weeks of research and experimentation building up to a dress rehearsal and the actual exhibit.
Learning about repeating patterns of eclipses and the different ways of measuring a month led me to create a series of Saros and Eclipse Explanimations.
Credits #
Eclipse Metacycles was installed at Curiosity Collider’s event, Total Alignment, and hosted by the H.R. MacMillan Space Centre. Curated by Char Hoyt.
Laser cutting was performed at Maker Labs.
Special thanks to my dad, Michael McLaren, for machining wood and acrylic dowels for the spinning tops. Check out his beautiful wood turning work.
Special thanks to Yasushi Harada for help with setup and teardown.