Sundials - World's Oldest Clocks

North American Sundial Society

Don’t miss the Solar Eclipse this Sunday, May 20th.  Times of the eclipse can be found at

For those of you in the San Francisco – San Mateo California area, Bill Gottesman, NASS dialist, has created an “eclipse clock”, a new type of paper sundial made specifically for the partial solar. You need a simple pin-hole projector (a card with a small hole in it) to cast a shadow of the eclipsed sun.  The angle of the moon’s shadow tells accurate time (at least for San Mateo California). Bill will discuss how he made this dial at the NASS Sundial Conference in Asheville this August.  Come find out how he did it.

Download this file (eclipsedial.pdf)Eclipse Sundial - May 20, 2012[Gottesman Eclipse Sundial for San Mateo CA]714 kB