A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2018 Mar 1, 16:41 -0800
Gary, you wrote:
"If this was done at the time of the [autumnal ] equinox would that explain why the alignment is off by four minutes of arc counter clockwise?"
That's why I was doing that math puzzle a few days ago. It's quaint that this was done as a "backyard" experiment since it's something that's been directly calculable with great accuracy for at least 250 years. Any date for two months around the equinox in the fall would yield a 6' counter-clockwise rotation that's at least a rough match because the Sun's declination shifts about 12' south in 12 hours from sunrise to sunset. But if you do the same surveying trick around either solstice, there's no rotation. And if you do it in the Spring the rotation is about 6' clockwise. Of course that means you can fit any case in the range from -6' to +6'. Thus the model always works. If every monument in some period of Egyptian history showed the same 6' CCW rotation, then this model might be onto something. Otherwise it's probably just fitting an equation to random noise.