As the winning entry for the Light Boston Lechmere Viaduct competition, moonPHASE is our take on illuminating this dark MBTA bridge that carries the Green Line over the Charles River near the Museum of Science in Boston. moonPHASE re-engages the head of the Charles River with the lunar cycles and changing daily tides. The span of the bridge will show a gradient of pastel hued light representative of the high and low tides each day, while the arches will pick up the color of tide at that particular moment, slowly cycling up and down. The causeway lights create a marker, cycling through the same cool to warm pattern as each night progresses. moonPHASE bears witness to the temporal relationship between celestial bodies, putting our tenuous relationship with our planet in context.