CDR-1367: SR Set: Coordinated Universal Time (UTC)

On June 30, 2015 a 'leap second' was added to make up the difference between International Atomic Time and Universal Time (or Astronomical Time). This event prompted us to explore the idea of time as it is represented visually in the Scholars Resource archive. The measurement of time began with the use of shadows cast by the sun as in sun dials or shadow clocks (among the earliest being ancient Egyptian obelisks). Over the centuries more elaborate instruments such as clocks, astrolabes, armillary spheres, etc. were developed particularly in pursuit of mapping celestial bodies for navigational purposes. The measurement of time remains an important element in navigation, be it for crossing the high seas in1492, navigating our quotidian life today, or traveling to the dwarf planet Pluto in the twenty-first century.