Dr. Jeremy Robinson, (Naval Research Laboratory, Electronics Science and Technology Division) combined efforts with his father-in-law, Prof. Woodruff Sullivan (Univ. of Washington Dept. of Astronomy) to construct the World's Smallest Sundial. The competition was sponsored by Cadrans Solaires pour Tous and their record is being entered into the Guiness Book of World Records.  

The sundial is not the traditional design that uses a gnomon to cast a shadow onto a dial.  In this sundial, the sun's image is projected through a small aperture through a transparent refractive medium onto a lithographically fabricated dial on the opposite side.  The dial has hour lines from 8AM to 4PM, and the seasonal lines of the winter and summer solstice limits of the sun and the equinox.  The sundial is too small to be read directly.  Instead, the assembly is mounted directly onto the image array of a webcam so that the sundial can be viewed on a monitor.

In 2004 Dr. Sullivan and Jim Bell with the support of The Planetary Society and Bill Nye, "The Science Guy" turned a camera color calibration wheel on the two Martian rovers Spirit and Opportunity into sundials. 17 years later the University of Copenhagen created a similar dial for the Martian rover Perseverence, with the motto  “Two Worlds, One Beginning”, which nicely refers to Spirit and Opportunity ’s  motto “Two Worlds, One Sun”.

Thanks for Eric Snow of the Northern Virginia Astronomy Club (NOVAC) for bringing this sundial feat to our attention.