[www.leapsecond.com]

Ten years ago I wanted to build a LED digital analog clock that would be accurate to better than one second per year — so I would have the fun of adjusting it when a leap second occurred.

This simple goal resulted in a most interesting journey into electronics, horology, astronomy, test equipment, quartz oscillators, rubidium and cesium atomic clocks, hydrogen masers, frequency counters and phase comparators, GPS, Loran C, GOES, and WWV / WWVB radio receivers.

By now I’ve exceeded that goal by a factor of a million: the best clocks in my collection (active hydrogen masers) are accurate to better than one microsecond per year. Excluding national government laboratories, my home time lab now has the most accurate clock in the world.

Perhaps you’ve heard: A man with one clock knows what time it is. A man with two clocks is never sure. But I would add further: A man with three clocks is more sure than a man with two clocks. And so the clock collection started…

…another fine link from Chris Samuel. 😎