Another place this Sirius alignment could have been taken from is Aswan, Egypt, for it is here that the Egyptian priests used to go to check the level of the Nile flooding by the nilometer. so may have used it to view Sirius as well.
Quote and link below:-
"The River Nile wasn't only a source of great mythology. It was a significant scientific site, by which ancient Egyptians created their Calendar. The rising of the Sirius star towards the East was the sign of the Nile Flood, namely on August 15th of the modern calendar, and the flood was in turn the beginning of the new ancient Egyptian Year. The ancient Egyptian year is divided into three seasons: flooding, planting and harvesting, each taking four months. Due to the importance of the Nile flood, ancient Egyptians created two Nile-meters to measure water levels in Aswan."

[egypt.travel]

[en.wikipedia.org]

[imgur.com]