You wouldn't think that the words accuracy and sundial would go hand in hand but a friend led me to a company called Precision Sundials that promises sundials that can accurately tell time. The Renaissance sundial shown here works buy using cylindrical focusing mirrors on the triangular support that project a sharply focused beam on the inside of the helix. There is a timescale inside the helix that reads to watch time within 30 seconds when properly set up. Even more amazingly, the timescale slides in its helical track so that it adjusts for daylight savings and the equation of time (seasonal variations in sundial time). The ball at the bottom allows you to set up the precise latitude for accurate measurement. Plus it looks like a cool piece of modern sculpture.
It weighs around 95 pounds and costs $8,000.
