Abstract

This article deals with an unstudied criterion for determining lunar crescent visibility, which appears in the Mufrad Z $$\bar{\iota }$$ ι¯ j,. Al-Ṭabar$$\bar{\upiota }$$ ι¯ attributes this circular criterion to Al-B$$\bar{\upiota }$$ ι¯ rūn$$\bar{\upiota }$$ ι¯. Initially, Prof. David King shed light on this criterion in 1987 and explained it briefly. We will examine this criterion by re-computing the underlying numerical values to reconstruct it, in order to demonstrate that it originates from Ḥabash’s simple criterion.