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.

中文翻译：

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Algol 作为开罗历法中的荷鲁斯：观察的可能手段和动机

摘要 古埃及的幸运和不幸日历，开罗日历 (CC)，将幸运分配给 2.850 天。先前对 CC 的天文、天体物理学和统计分析支持这样的观点，即这是三千年前食双星大陵五的时期。然而，关于谁将 Algol 的时期记录到 CC 中，尤其是如何记录的，几乎一无所知。在这里，我们表明古埃及的抄写员有可能进行这种天文观测的手段和动机。他们将天体现象描述为众神活动的原则揭示了为什么 Algol 获得了荷鲁斯的称号。