National Museum of American History

Atomic Clock (Hydrogen Maser)

August 25, 1980 – November 15, 1981

Observe the original Hydrogen Maser, the most stable and precise of atomic clocks, invented by Norman F. Ramsey of Harvard University.

1st Floor, Entrance to "Atom Smashers"

Free, no passes needed

10 a.m. to 5:30 p.m. daily
Closed Dec. 25