Sundials

Simple and beautiful, sundials are one of the few historical tools we find in use today. The sundials in the Adler collection come in many shapes, sizes and materials. We have included several of our more interesting types in this virtual exhibit, along with common ones like the stone English garden sundial shown above.

Sundials consist of at least one surface, with a dial denoting the hours (The pentagonal sundial on the left is a dodecahedron designed to tell time at 10 different latitudes). Sundials are labelled with the morning hours on the left and the evening hours on the right. A stick, called a gnomon, is set into the surface at the same angle of the user's latitude. In Chicago, we set our gnomons around 42 degrees. In the northern hemisphere, the gnomon must point to the north in order for the sundial to work. In the southern hemispheres, the gnomons need to point south. Where the shadow falls determines the time.

Sundials are made of many materials. Both the pentagonal sundial above, and this more intricate multi-sided sundial to the right, and the Chinese bowl sundial below are made of brass. This is an expensive choice for common people, so many sundials in were make of stone. The other two Chinese sundials below were made of ivory and wood. You can make a sundial of your hand, too. Hold a stick between your thumb and forefinger of your hand at an angle equal to your latitude, and face south, so that the gnomon points north. In the morning, you need to use your left hand. In the afternoon, you need to use your right hand. Look to see where the shadow falls. In the example below left, the "sundial" reads 11 o'clock in the morning. The diagram below right shows how to read the "dial".

Sundials come in many sizes. The brass sundials above are about two feet high. The ivory and wood sundials here were "pocket" sundials, early "pocket watches."

The bowl sundial is about one foot across. The record, at least for Adler sundials, is the familiar sundial that has greeted visitors in front of the Adler Planetarium for decades. It was moved during the constructions of the new sky pavillion, and now it's new home is few yards north and east of it's old position.

Come and visit us --any "time"!