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13. Greenwood Elementary School


On NW 80th St just east of 3rd Ave NW, Seattle; large horizontal dial at east entrance to school  

Designers: Woody Sullivan and Larry Stark
Fabricator: Larry Stark
Dimensions:  ; pattern over a ~40 ft (12 m) wide area; nodus on a pole 10 ft 10 inches (3.30 m) above the pattern
Material:    stainless steel pole and aperture plate; colored concrete for pattern lines

47°41´13.9˝ N     122°21´33.7˝ W

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Rather than the usual gnomon for a horizontal dial, this sundial has a nodus, meaning a reference point (in this case an aperture), that casts a spot of sunlight on to the concrete surface of the area outside the school entrance.  The nodus is a 6 inch (15 cm) diameter hole in a 24 inch (60 cm) diameter horizontal disk held at a height of 10 ft 10 inches (3.30 m) by a stainless steel pole. This creates a moving spot of light (which is surprisingly always circular in shape) that tells the time and allows the date to be estimated, too. The solstices and equinox lines, as well as the hour lines, are defined by color-stained concrete strips. The pattern area is extremely irregular in shape (defined by the building, exterior stairs, etc.), but the equinox line was made such that it proceeds directly into the center of the school doors.

    This dial was part of a renovation (completed in 2002) of the school, which dates back to 1909. It grew out of the fact that Larry Stark’s daughter Ruth was a student at the school and Woody Sullivan worked on astronomy topics with fourth-grade teacher Pat Kemp in the 2000-01 school year. It works well (~5 minutes accuracy), but, as the photos show, also illustrates a classic example of a communications screw-up in a large construction project. Sullivan and Stark worked well with the project architects and construction team, but never learned that there was to be a security chain-link fence placed between the pole and the dial pattern! This ruins the aesthetics of the dial and means that when the sun is highest near the summer solstice the shadow of the fence interferes with the spot of sunlight (but at least the fence is not a wall!).

Last seen: 2009