"Skylight Aperture Sundial"

Artwork by Rebecca Cummins at the Montlake Branch
Artwork by Rebecca Cummins at the Montlake Branch

Longitude 122°18.2

Latitude 47°38.4

"Skylight Aperture Sundial" features a row of five circular openings in the ceiling, which are covered by colored glass discs of purple, teal, green, aqua and orange. The glass discs project colorful spotlights that float through the library as the sun moves across the sky. At night, artificial lights illuminate the colored discs.

Between the spring and autumn equinoxes, circles of light slide across the space throughout the day. After the summer solstice (about June 21), the spotlights move daily north until the autumn equinox (Sept. 23). As the sun appears lower in the sky in autumn and winter, ceiling beams block the spotlights, but they reappear near the spring equinox (March 20). In the winter and on overcast days, the light from the sky causes the colored discs to glow overhead.

The orange spotlight is the time indicator for the sundial; the other spotlight colors are decorative. A dashed line of steel markings in the floor designates the "solar noon line." When the orange spotlight crosses the line, it is solar noon. A marker also indicates solar noon on Aug. 12, 2006, the day the Montlake Branch opened, and "clock noon" on the summer solstice and equinoxes.

Artist's Inspiration

The concept for this artwork evolved while I was observing an architectural model of the Montlake Branch on a heliodon - a "sun machine" that simulates the sun's path for various times of day and year. Light tracks in wondrous and often surprising ways; it was exciting to watch the simulated sunlight glide through the proposed space. I aspired to communicate this movement in the artwork.

With the circular holes in the ceiling, the library becomes a small observatory, much like some 17th- and 18th-century European cathedrals used by astronomers.

About the Artist

Cummins received her doctorate at the University of Technology, Sydney, Australia, in 2003. She is an associate professor at the University of Washington and in 2003 co-taught a sundial course with astronomy professor Woodruff Sullivan.