Applying Solar Geometry To Understand the Foundation Rituals Of 'old Kingdom' egyptian Pyramids

摘要

The republication of the interesting book by Rossi (2003, 2007) has provoked questions about the orientation of Egyptian pyramids from the architectural science point of view. The main concern of this paper is to explain several hypothetical possibilities for orientation of the first step Egyptian pyramid. The oldest monumental step pyramid complex, at Saqqara, was built by Imhotep in the 3rd millennium BC, 3rd Dynasty of the 'Old Kingdom'. Pre-construction involved a foundation ritual, during which the pyramid's south orientation and plan were determined by 'stretching the cords', a site design procedure partially illustrated on stone engravings. Though helpful, these illustrations incompletely depict the method of pyramid plan design and orientation. Due to rhombic signs on mastaba foundation stones, some Egyptologists claim that geometry was the primary method used for pyramid plan design and orientation. However, due to the solar equinox festive day and the pharaoh's presence at the festival, it is possible that the solar equinox was the day chosen for the ceremony. During the equinox, the gnomon shadow would directly indicate the E-W cardinal points. It is plausible, therefore, that solar geometry, at the equinox, was chosen to establish the primary orientation of the pyramid complex. Sundials based on the equinox sun-shadow were commonly used during the 3rd century BC. This paper discusses methods that could have been available to determine the orientation of pyramids.