Sundial built in student courtyard

The Blair astronomy class recently finished constructing a sundial in the student courtyard that uses natural light to determine time, according to astronomy teacher Leslie Rogers. The sundial cost around $125 and is accurate within 15 minutes of the actual time.

New Painted Sundial

Photo: Blair's new sundial that uses natural light to tell the time can be found in the student courtyard.

Blair's new sundial that uses natural light to tell the time can be found in the student courtyard. Photo courtesy of Bridget Egan.

The astronomy class began the course by studying the history of sundials. Rogers taught the students that telling time from the sun was derived from telling time by using the Big Dipper, or the Ursa Major.

The class made personal sundials and then progressed to the larger one in the courtyard. Construction of the sundial took them three class days to complete.

Rogers has high hopes for the future of the sundial. "I think with regular watering of the shrubs it will be there forever," he said. The thirteen shrubs each represent an hour.

Rogers also hopes that the public display of the sundial will encourage students to take the course. "I believe that it is a recruitment technique," he said.

While creating a lasting monument at Blair was important to Rogers, having the students work as a group for a common goal was also memorable. "Having the kids work together as a team was the most powerful outcome," he said.

How to read the sundial

Surrounding the gnomon which is the protruding piece of wood at an angle are thirteen shrubs, each representing an hour. If facing north, the direction the gnomon points towards, the first plant on the left represents 6 a.m. and the last plant on the right represents 6 p.m.

Due to the curvature of the earth, the sundial is not completely accurate. The Equation of Time, posted on a small wooden block near the sundial, shows students how to subtract or add minutes according to the date to determine the actual time.