USNO Clock Vault, Washington, DC
A Brief History of USNO Timekeeping
Precise Time & the USNO Master Clock
The USNO Time Scale
International Time Scales and the BIPM
Definitions of Systems of Time at USNO

Top | The USNO Master Clock | What Time Is It? | GPS and Other Timing Operations | Automated Data Service | Computer Time Services | Two-Way Satellite Time Transfer | PTTI Meeting |

"Time is a great teacher, but unfortunately it kills all its pupils."-Hector Berlioz