USNO

From DictionGloss

United States Naval Observatory

Established in 1830, the USNO is one of the oldest scientific agencies in the United States. The USNO determines and distributes the timing and astronomical data required for accurate navigation and fundamental astronomy. It maintains a UTC time scale that is (by mutual agreement) within 100 nanoseconds of UTC(NIST). Both NIST and the USNO can be considered official sources of time and frequency in the United States.