Ask DCist: What's Up with the Naval Clock?

A couple of readers have written us to ask why the Master Clock at 34th Street and Massachusetts Ave NW, at the entrance of the U.S. Naval Observatory, hasn't been working for the last few months.

We asked Geoff Chester at the USNO Public Affairs Office, who told us that the clock "had a little trouble dealing with the heat of a D.C. summer. So it's back at the vendor getting fixed while we design a new enclosure for it that will have better ventilation." Once it's ready, you can get back to setting your watches to the most precise clock in the world.

The Master Clock is a type of atomic clock that uses a hydrogen maser (rather than cesium), making it a highly accurate short-term time keeping system. The Naval Observatory keeps it accurate over the long term "by making regular observations of the Sun, Moon, planets, selected stars, and other celestial bodies to determine their positions and motions." The entire U.S. military synchronizes to this time for their navigation and other operations. The only thing currently being fixed is the display; the clock (actually 45 clocks, of which the time is derived from the mean) is still running just fine.