Sundials - World's Oldest Clocks

North American Sundial Society

A sundial that only tells time during an eclipse?  Back in 2012 Bill Gottesman designed a peculiar dial to tell time by observing the angle between the cusps of the sun during the May 2012 eclipse.  Bill Gottesman is back at it with a more sophisticated version assisted by programmer Dan Axtell.  This time Bill and Dan give you an animated version of the cusp line, as well as detailed information of the line angle during the eclipse.  

This is for anywhere in North America that can see the partial or total eclipse.  Just enter your latitude and longitude and let the software create you a personal solar eclipse sundial. PLEASE DO NOT OBSERVE THE SUN DIRECTLY WITHOUT AN APPROVED SOLAR FILTER... OR, MAKE A SIMPLE PINHOLE CAMERA FROM A CARDBOARD BOX.

To make your solar eclipse sundial, go to