Multimedia Gallery
- Topic: Timekeeping
Quartz oscillator used to control radio frequency on Transit satellites.
Set in an electrical circuit, a crystal resonator vibrates regularly and becomes an oscillator to control radio frequencies.
Navigators used radio time signals to accurately set their second-setting watches. Stations around the world broadcast these time signals hourly.
This atomic clock was built for the first GPS satellites in the late 1970s.
The GPS Operations Center at Schriever Air Force Base in Colorado Springs controls the GPS satellites.
Sandia National Laboratories researcher Darwin Serkland measures the wavelength of a tiny laser for chip-scale atomic clocks.
Sidereal time, or “star time,” is based on Earth’s rotation relative to the stars, rather than to the Sun.
Marine Chronometer, signed William Bond & Son, about 1867.
The hand-held GPS receiver was used for tasks such as land surveying and providing accurate time.
The U.S. Naval Observatory Alternate Master Clock at Schriever Air Force Base.