Buried in the middle of Sefer Raziel HaMalakh is a detailed astronomical and calendrical section that reads more like a scientific manual than a mystical text. It catalogs the movements of the sun and moon, the lengths of the seasons, the positions of the stars, and the proper times for prayer, planting, and travel—all framed as knowledge that the angel Raziel revealed to Adam so that humanity could navigate time itself.
The calendar section divides the year according to the Jewish lunisolar system, tracking the molad (מולד)—the moment of the new moon's birth—for each month. It identifies which hours of which days are governed by which angels and planets, creating an elaborate grid of sacred time. The first hour of Sunday belongs to the sun and the angel Michael. The first hour of Monday belongs to the moon and the angel Gabriel. This system, known as planetary hours in medieval Jewish texts, determined when certain prayers, amulets, and adjurations would be most effective.
The astronomical material in Sefer Raziel reflects genuine observational knowledge. The text describes the sun's annual path through the sky, the varying lengths of day and night across the seasons, and the 19-year Metonic cycle—the period after which the phases of the moon recur on the same days of the solar year. This 19-year cycle was well known to ancient astronomers and forms the basis of the Hebrew calendar's intercalation system, which adds a leap month seven times in every 19-year cycle.
The text also discusses the mazalot (מזלות), the zodiac constellations, assigning an angel to each sign. But unlike Greek astrology, Sefer Raziel insists that the stars do not determine fate. They are instruments of <strong>God's</strong> will, readable by those who have the knowledge but always subordinate to divine providence. As the Talmud states: "Ein mazal l'Yisrael"—Israel is not subject to the stars (Shabbat 156a).