Star Clocks (Egyptian)

Definition

Egyptian star clocks are diagram-tables of rising decans — found on Middle Kingdom coffin lids and New Kingdom tomb ceilings — that let Egyptian priests tell which decan was rising at each hour of the night, throughout the year. There are two main kinds: the diagonal star clock on coffin lids, and the Ramesside transit star clock on tomb ceilings. Both work the same way: the thirty-six decans take turns as the night's hour-markers across the ten-day Egyptian week.

In Tradition

Egyptologists (Clagett; Belmonte-Lull; Neugebauer-Parker) read star clocks as the working tool of the decan system. Their job is to turn the abstract spread of thirty-six decans across the year into a usable nightly hour-table, so a trained watcher could read the hour from whichever decan was currently crossing the sky (the Ramesside type) or rising on the horizon (the diagonal type). They are the earliest surviving systematic star-charts and the practical instrument of Egyptian temple ritual at night.

In Practice

Star clocks are studied today as history and as museum objects, not as astrology. Astrologers and historians of astronomy turn to images of them as the main visual evidence for the Egyptian decan system, and as the source material for the decan images that Hellenistic astrology later inherited. The standard tools are Clagett's critical edition (Volume II, Documents III.11 and III.14), the Neugebauer-Parker Egyptian Astronomical Texts series (1960-1969), and the Belmonte-Lull synthesis. The decan images on these star clocks lie behind much of the decan iconography in the later Liber Hermetis and Picatrix.

Historical Origin

The earliest surviving diagonal star-clocks are on Ninth-Tenth Dynasty coffin lids from Asyut and Gebelein (around 2150-2050 BCE). The Senenmut tomb (TT 71, around 1473 BCE) and the Cenotaph of Seti I (around 1290 BCE) preserve elaborate versions on their ceilings. The Ramesside transit star clock survives in the Cenotaph of Seti I and in the tombs of Ramesses VI, VII, and IX; Clagett (Document III.14) is the critical edition.

Definition

In Tradition

In Practice

Historical Origin

Further Reading