Sundials - World's Oldest Clocks

North American Sundial Society

Larisa N. Vodolazhskaya of the Department of Space Physics at Southern Federal University (SFU), Rostov, has brought two ancient time keepers together with a new and startling result.  The story starts at the turn of the end of the 19th century with the discovery of an L-shaped bar found in the tomb of Thutmose III (1479-1425 BCE). that appeared to be a sundial. In the 1930's a "user manual" of sort was found carved on the tomb ceiling of Seti I (1290-1279 BCE) at Abydos. The ideal L-shaped bar had lines engraved with distances from a starting mark of  3, 6, 9, and 12 units. The Seti I text describes these spacings as "an established procedure".  But what is the procedure?

Then in March 2013 during the excavation of rubble associated with worker huts of Ramesses II (1279-1213) in the Valley of the Kings, Professor Dr. Susanne Bickel and her student archeological team from the University of Basel found one of the oldest sundials in the world.  It is a vertical dial of limestone with what appear to be crudely drawn hour lines. The Basel team found a poor fit using hour lines with15o spacing expected of a traditional “unequal hour” sundial with horizontal gnomon.

Dr. Vodolazhskaya of Department of Space Physics at Southern Federal University (SFU), Rostov,
shows relation between tradition L-shaped Egyptian solar indicators and Egyptian vertical dial discovered
in the Valley of the Kings by the University of Basel in March 2013

Dr. Vodolazhskaya analyzes the use of these two sundial objects together, showing that the Valley of the King dial has accurately drawn hour lines that can be constructed by the L-shaped bar. The simple spacing distances of marks on the bar (ideally 1, 3, 6, 9 and 12) are measured for two L-shaped solar indicators held in the Berlin Museum.  The ratios are close to ideal, but not exact. Vodolazhskaya argues that these differences of L-shaped solar markings are intentional: one for marking (or interpreting) the morning hours of a vertical dial, and another for marking the afternoon hours where the lines are offset by half an hour. Vodolazhskaya speculates,"we associate the half-hour shift in the markup with the need for ...midday rest for workers - the traditional siesta ..."

Dr Vodolazhskaya shows that Egyptian time telling was far more advanced than previously credited, but done in such a way that only the cognoscenti, the priesthood who held the L-shaped bar, could draw the lines of a sundial to create sundials with astounding accuracy of time. Her analysis is significant, showing that the Valley of the King dial using "equal hours" implies a gnomon pointed to the north celestial pole.  This Egyptian feat would not be replicated again for nearly 3000 years until the Arab Ibn al Shatir constructed the first "modern" sundial at the Great Mosque in Damascus in 1371 CE.

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