Instrument 09 / chosen beginnings
Epoch Clock
Unix seconds--
Julian Date--
GPS time--
Civil calendar
Tamil solar calendar--
GPS uses an embedded leap-second table through 2016-12-31. NIST leap-second record
Tamil solar date -- astronomical approximation. The month follows an approximate sidereal solar longitude. Almanac conventions and local day-boundary rules vary. Scholarly calendar overview
Why this clock exists
The U.S. Naval Observatory describes Julian Date as a continuous count beginning at noon on January 1, 4713 BCE in the Julian calendar. Unix, GPS, civil, and Tamil solar readings choose other origins and rules. This stack gives one device instant five names. None is the natural label hiding underneath the others; each count works because a community agreed where to begin and how to continue.
U.S. Naval Observatory Julian Date converter