From September 5 though October 25, Echoes & Evolutions: Nancy Holt’s Sun Tunnels is on show at Sprüth Magers, New York. Sun Tunnels is a landmark in the Holt's oeuvre and encapsulates her investigation of perception, systems and site. Showcasing many previously unseen drawings, collages, photographs and two of her Studio Locator sculptures, this exhibition offers insight into the process and ideas behind the creation of Sun Tunnels.

Based on meticulous calculations, the tunnels are positioned precisely to frame the sun as it rises and sets during the summer and winter solstices. Configurations of circular holes puncture the concrete surfaces, and through them light emanating from the sun and moon cast projections of specific star constellations inside the tunnel interiors. Drawing for Positioning of Holes in the Perseus Constellation for One Tunnel of "Sun Tunnels" (1975) is one of the drawings that serves as a study for these perforations. In selecting the respective constellation for each tunnel, Holt carefully chose star clusters of different magnitude, allowing for views from both inside and outside the tunnel. “With those criteria there were only a few constellations that I could use, and from them I chose Draco, Perseus, Columba, and Capricorn.” (From Nancy Holt’s Sun Tunnels, originally published in Artforum, April 1977, Vol. 15 No. 8).

Part of Holt's process involved using cardboard tubes to model potential configurations, which she photographed to understand the shifting shadows and scale of the work. In these photo studies from 1975, Holt experimented with the layout of the tunnels, trying out sizes and configurations of the star constellations. On the back of each photo study are Holt’s annotations about the orientation, time, and constellation she was testing. Through this expansive series, patterns in her practice emerge that illustrate her systematic approach to making sculpture. This is emphasized again in Sunlight in Sun Tunnels and Sun Tunnels: Shifting Shadows (both 1976) in which Holt charted the evolving light and shadow at regular intervals over the course of one day respectively, bringing together the process into a single photographic composite.

Also on view are two Studio Locators, Holt’s first sculptures made in 1971 that directly led her to create Sun Tunnels . A simple structure made from a steel pipe mounted at eye-level, the Locators can be understood as a telescope without a lens, framing a particular field of vision in space. Holt’s Studio Locators focus on specific details and, when presented today, their position sustains her careful choice of locating vision, highlighting her interest in the sculptural forms of the often-overlooked systems in the built environment. Originally directed out of a window in Holt’s New York studio on Greenwich Street, the view from the Locator always features the architectural detail noted in the work title. Locator (Exhaust Pipe) looks up to a roof ventilation pipe, while Locator in Window—the first of her Studio Locators—focusses vision on a single point directed by the Locator.