Invisible Sky

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Installed in the American Philosophical Society's Jefferson Garden, Philadelphia, PA. This was the second of three commissions for the Museum of the American Philosophical Society to coincide with and complement their exhibition, Undaunted: 5 American Explorers.
November 2007 through March 2008

Materials & Dimensions:
Blown glass, aluminum, LEDs, electric circuitry
37.5 feet diameter x 4-5 inches high; glass half spheres vary 2"-6"diam

The solid blown glass hemisphere lenses range from 6" diameter to 2" diameter, and were mounted on aluminum LED fixtures designed by the artist and set into the lawn area with connecting underground circuitry. The lenses were laid out in the pattern of the constellations containing the stars that were most frequently used by Charles Mason and Jeremiah Dixon in their autumn astronomical observations for the surveying of the boundary between Pennsylvania and Maryland. The varied diameters of the lenses corresponded to the brightness of the stars in each constellation. Arcs of square section aluminum bar stock were inlaid in the lawn to diagram the circle of the horizon.

This was a star map for 11 constellations in the October sky. The map was oriented to the appropriate cardinal points, but as it would be on a map in a book before it was turned over and lifted to read the sky. October was selected because it is the month when Mason & Dixon had to stop their survey of the line because they had come to the warpath of the Six Nations and their Mohawk guides told them they could go no further due to the danger.

During the day the glass hemispheres functioned like fisheye lenses or Victorian gazing balls and reflected the surrounding garden and buildings, and any changes in the environment (i.e.-birds flying over head, the color of the sky, changing cloud formations, people walking around to view them). At night the lenses were lit from within by LEDs while still reflecting the night lights of surrounding streets and buildings. Thus the shape and function of the lens lights reciprocated the geometry of the space depicted by the star map except that the lens lights actively accommodated and revealed phenomena of the environment and the participant's position. Also, the otherwise unlit and locked garden was made mysterious and desirable at night by the inexplicable field of blue-white lights that seemed to float above the grass just beyond reach of definition. It was a surrogate for the starry sky that municipal light pollution has made invisible.