An excerpt from a LiveScience piece:
[...] Ancient Alexandria was planned around a main east-west thoroughfare called Canopic Road, said Giulio Magli, an archaeoastronomer at the Politecnico of Milan. A study of the ancient route reveals it is not laid out according to topography; for example, it doesn’t run quite parallel to the coastline. But on the birthday of Alexander the Great, the rising sun of the fourth century rose “in almost perfect alignment with the road,” Magli said.
The results, he added, could help researchers in the hunt for the elusive tomb of Alexander. Ancient texts hold that the king’s body was placed in a gold casket in a gold sarcophagus, later replaced with glass. The tomb, located somewhere in Alexandria, has been lost for nearly 2,000 years. [8 Grisly Archaeological Discoveries]
Building by the stars
Magli and his colleague Luisa Ferro used computer software to simulate the sun’s position in the fourth century B.C. (Because Earth’s orbit isn’t perfect, there is some variation in the sun’s path through the sky over centuries.) Alexander the Great was born on July 20, 356 B.C. by the Julian calendar, which is slightly different than the modern, Gregorian calendar, because it does not have leap years to account for partial days in the Earth’s orbit around the sun. On that day in the fourth century B.C., the researchers found, the sun rose at a spot less than half a degree off of the road’s route.
“With a slight displacement of the day, the phenomenon is still enjoyable in our times,” Magli told LiveScience.
A second star would have added to the effect, Magli said. The “King’s Star” Regulus, which is found on the head of the lion in the constellation Leo, also rose in near-perfect alignment with Canopic Road and became visible after a period of conjunction with the sun near July 20. Earth’s orbit has changed enough that this Regulus phenomenon no longer happens, Magli said. [...]
- via: Ancient Egypt City Aligned With Sun on King’s Birthday (Live Science)
… I wonder how they account for the half-degree-out-of-alignment; must look into this further …
UPDATE (a few minutes later): this appears to be the original paper the article is based on (pdf) … that link doesn’t appear to want to work, though, so cut and paste this into your address bar: arxiv.org/pdf/1103.0939