Cassini’s Nocturne references the 17th Century French philosopher who discovered why the sun looks flat when it is on the horizon. In the sculpture, the inner layer of frosted glass has a clear oval polished into its center. This is where the light passes through. The oval shape distorts as the scrim behind it is pushed and released by the mechanism behind the glass.
As air passes through layers of the atmosphere with different temperatures, it bends the light. The atmosphere, particularly in the early morning, usually has a layered structure; air temperature changes with height. If the sun is on, or just above the horizon, the light travels along a long path through the atmosphere. As the light passes through these different layers, it will refract and deform, flatten or distort the sun’s disk. Light rays coming from the top of the sun bend less than rays coming from the bottom, slightly squashing the sun’s circular shape.