Archeoastronomy: Egypt: Stretching The Cord

Stellar Method of Determining Cardinal Points

Stretching The Cord

Navigating by the stars has been done by people for thousands of years. To find North today, people simply look for Polaris in Ursa Minor (The Little Dipper). (In the Southern Hemisphere, North would be determined by using the Southern Cross.) Since precession, which is the change in orientation of the Earth’s Axis, occurs every 26,000 years, the “North Star” changes through time. For example, during Roman times, there was no such star. However at the time of the building of the pyramids, it was Alpha-Draconis known to the Egyptians as “Thuban.”

The U.S. Army suggests that in order to go North, a person should walk towards the point on the horizon directly below Polaris. Another method is to select a circumpolar star such as Vega of Lyra, the second brightest star in the night sky. Measure the angle from the viewer to Vega’s rising and to its setting. The bisection of this angle will give the exact location for true North.

In ancient Egypt, the orientation of their buildings mattered, for the Pharaoh received his power from the Northern Stars. After his death, the soul of the Pharaoh went to the “Mooring Post” in the North by way of the Milky Way. In the ceremony, “The Stretching of the Cord” (Pedj shes), the Pharaoh determined the direction of North with the help of the Goddess Seshat.

 Several archeologists have suggested one method that the ancient Egyptians may have used for finding directions. To orient their buildings, they would have to bisect the angle of a circumpolar star. First they would erect a round wall. Then one person stood on a selected spot and looked through a “bay,” a straight pole with a forked top. As he sighted a circumpolar star such as Vega rising, a second person would use a “merklet,” a plumb line, to mark the spot. Around the circular wall at various timed intervals, they would mark the position of the star. The final marking on the wall would be the star’s setting. After measuring the angle formed by the star’s rising and setting to the first observer, the Egyptians could bisect it, and determine true North.

Kate Spence, of the University of Cambridge (U.K.), wrote that the Egyptians probably used Mizar (Eta Ursae Majoris) of the Big Dipper and Kochab (Beta Ursae Minoris) of the Little Dipper. (Both are circumpolar stars.) The Egyptians constructed a scaffold and hung a string with a heavy weight from it. This weight would point to the center of the Earth. When these two stars became aligned with the string, the line from the person, who was doing the sighting, to the string would point due north to the horizon.

From the First Dynasty to the end of the Ptolemaic Dynastry, the Pharaoh conducted the sacred ceremony, “Stretching of the Cord,” to orient the temples and tombs before building them. Facing the Goddess of Wisdom and Knowledge, Seshat, the Pharaoh stood with a hammer in one hand and a pole in the other. Holding the same items, the Goddess and the Pharaoh then pulled a cord that was wrapped between their respective poles. The Pyramid Texts described the ceremony as: “I have grasped the stake…I take the measuring cord in the company of Seshet. I consider the progressive movements of the stars. My eye is fixed upon the Bull’s Thigh [Ursa Major]. I count off time…and establish the corners of the Temple.” This is how the Pharaoh determined North from whence came his power, and to where his soul traveled.

Works Used.

Aveni, Anthony, “People and the Sky,” Thames & Hudson: N.Y, 2008.

 Belmonte, Juan Antonio; Molinero, Miguel Angel and Miranda, Noemi, “Unveiling Seshat: New Insights into the Stretching of the Cord Ceremony,” In Search of Cosmic Order: Selected Essays on Egyptian Archaeoastronomy, Juan Antonio Belmonte and Mosalam Shaltout, eds., Cairo: Supreme Council of Antiquities Press, 2009, 197-212.

 Houlding Deborah, “Time, The Egyptians and the Calendar,” Heritage of the Stars, 2003, http://www.skyscript.co.uk/heritage/egyptians.html, .

 Magli, Giulio, “Mysteries and Discoveries of Archaeoastronomy,” Copernicus Books: N.Y., 2009.

 Stecchini, Livio, “Methods of Finding Cardinal Points,” World Mysteries, 2004, http://www.world-mysteries.com/alignments/mpl_al3.htm#Cardinal, .

“Orientating Egyptian Pyramids,” World Mysteries, 2004, http://www.world-mysteries.com/alignments/mpl_al4.htm, , .

 U.S. Army, “Field Expedient Methods of Determining Directions,” Army Study Guide, 2014, http://www.armystudyguide.com/content/army_board_study_guide_topics/land_navigation_map_reading/field-expedient-methods-of-determining-direction.shtml, .

Archeoastrotronomy: Finding Directions by the Sun

Solar method of Determining Cardinal Points

Finding cardinal points (the directions of north, south, east, and west) can be done by using the sun.  One simple method is to watch the sun rise or set, which would tell you which direction was east or west. Therefore, north and south would be perpendicular to the east-west axis. This is one way to find geographical north.

 The U.S. Army suggests using a more precise method in determining the cardinal directions. Place a tall stick upright on level ground. (On a sundial, this upright stick would be the gnomon.) Mark the shadow that forms from the sun striking the gnomon. Place a line perpendicular at the tip of this shadow. This marks the western direction, but is not precisely west.

 Then wait at least ten or more minutes, and mark the tip of the new shadow formed by the gnomon. For greater accuracy, wait again for another ten minutes, and then mark that shadow tip as well. Draw a straight line between these three points. This becomes the east-west line. To find the north-south line, stand with the direction of west on your left. Now you are facing north. This north-south line bisects the east-west axis at right angles. (For telling time, the crossing of the two axis is the noon line.) 

 Because finding directions was a sacred obligation for the ancient Egyptians, they did more precise measurements. To them, the Land of the Dead, where the Soul goes, laid in the west. Therefore their tombs including The Pyramids would have an entrance facing west. The ancient Egyptians probably used one of their obelisks as a gnomon. By tracking the shadows formed at the solstices and equinoxes, the ancient Egyptians could construct a more accurate basis for the north-south and east-west lines. Moreover, the obelisk, acting as the gnomon, would cast a moving shadow throughout the day. When this shadow was marked each hour, the radii of a circle were formed. In this manner, directions such as northwest could also be determined.

Finding the cardinal directions requires you to observe the movement of the sun. For accuracy, a stick and patience are needed. By using the stick as a gnomon, you can mark the various shadows formed as the sun moves across the sky. In this manner, you can determine the actual directions. With repeated observations throughout the year, a precise line for each direction could be constructed for religious purposes.

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The sun moves north and south of east and west as the seasons progress and thus only marks true or exact east and west for a small portion of the year. 

 Works Used.

Aveni, Anthony, “People and the Sky,” Thames & Hudson: N.Y, 2008.

 Duke, Dennis, “Four Lost Episodes in Ancient Solar Theory,” Florida State University, 2008, http://people.sc.fsu.edu/~dduke/episodes3.pdf, .

 Magli, Giulio, “Mysteries and Discoveries of Archaeoastronomy,” Copernicus Books: N.Y., 2009.

 ----, “Methods of Finding Cardinal Points,” World Mysteries, 2004, http://www.world-mysteries.com/alignments/mpl_al3.htm#Cardinal, .

 U.S. Army, “Field Expedient Methods of Determining Directions,” Army Study Guide, 2014, http://www.armystudyguide.com/content/army_board_study_guide_topics/land_navigation_map_reading/field-expedient-methods-of-determining-direction.shtml, .