Editing United States Naval Observatory (section)

===The time ball===
The first superintendent was Navy Commander [[Matthew Fontaine Maury|M.F. Maury]]. Maury had the world's first [[Vulcanization|vulcanized]] [[time ball]], created to his specifications by [[Charles Goodyear]] for the U.S.&nbsp;Observatory. Placed into service in 1845, it was the first time ball in the United States and the 12th in the world. Maury kept accurate time by the stars and planets.

The time ball was dropped every day except Sunday, precisely at the astronomically defined moment of [[noon|mean solar noon]]; this enabled all ships and civilians within sight to know the exact time. By the end of the American Civil War, the Observatory's clocks were linked via [[Telegraphy|telegraph]] to ring the alarm bells in all of the Washington, D.C. firehouses three times a day.

The USNO held a one-off time-ball re-enactment for the year-2000 celebration.<ref>{{cite APOD |title=The USNO millennium time ball |date=1999-10-29 |access-date=2015-12-27}}</ref>