The Geochron allows any observer to determine what time it is anywhere in the world. Physically the Geochron looks like a framed world map, about 2×3 ft. in size. The colorful map itself is an endless belt that is driven slowly from left to right by an electric clock motor in synchronism with the rotation of the earth. All known legal time zone boundaries are delineated on the map by dark blue lines which in most cases, converge on lettered pointers on the top edge of the map. These letters identify the standard time zones and also represent the short wave radio prefix for that zone.

Specifically, the Geochron illustrates:

• Legal time zones
• Greenwich Mean time
• Greenwich Apparent time
• Local Apparent time
• Moment of sunrise
• Moment of sunset
• Duration of daylight
• Sun’s meridian passage
• Sun’s equation of time
• Degrees of latitude and longitude