Algol as Horus in the Cairo Calendar: the possible means and the motives of the observations

TL;DR

This paper explores how ancient Egyptian scribes might have observed and recorded the Algol star's period in the Cairo Calendar, linking celestial phenomena to divine activity and motives.

Contribution

It proposes that ancient Egyptian scribes had the means and motives to record Algol's period, explaining the astronomical and mythological context of their observations.

Findings

Algol's period was likely recorded in the Cairo Calendar.

Egyptian principles linked celestial phenomena to gods, explaining the recording.

Horus was associated with Algol, reflecting divine attribution.

Abstract

An ancient Egyptian Calendar of Lucky and Unlucky Days, the Cairo Calendar (CC), assigns luck with the period of 2.850 days. Previous astronomical, astrophysical and statistical analyses of CC support the idea that this was the period of the eclipsing binary Algol three millennia ago. However, next to nothing is known about who recorded Algol's period into CC and especially how. Here, we show that the ancient Egyptian scribes had the possible means and the motives for such astronomical observations. Their principles of describing celestial phenomena as activity of gods reveal why Algol received the title of Horus.