This sundial is a memorial to our son Aaron as well as a precision astronomical instrument capable of telling the time to within a minute. Unlike any other sundial, it combines the measurement and display of both time and space. The shadow of the gnomon (the black wire with the metal bead) indicates the time, while the shadow of the bead indicates the point at which the Sun is currently directly overhead. This sundial is a copy of the Longitude Dial invented by William Andrewes of Concord, Massachusetts, who graciously permitted us to reproduce it and place it here as Aaron's memorial.
Both the map and the time measuring components of the sundial are designed specifically for its location at Mount Auburn Cemetery, which corresponds to the center of the sundial’s map marked by a small circle. The map itself is a gnomonic projection that is generated by projecting points on the Earth’s surface to a flat plane that touches the Earth exactly at the sundial’s location (see the Theory section of this website for additional details about the map).
The curved lines on the map represent the birthdays of Aaron and the other family members which the Sun will trace out on their respective dates. The Sun will follow the line of the equator on the Spring and Autumn equinoxes and the line of The Tropic of Cancer on the Summer solstice.