Al Dhira

Al Dhira is the seventh lunar mansion, spanning roughly 77 to 90 degrees within Gemini, in the region of the bright stars Castor and Pollux. Its name means the forearm, referring to those two stars as the outstretched arm of the constellation. In the manazil tradition its planetary ruler is Saturn, and its traditional talismanic virtue is gain and love, favourable for winning affection and profit. Each of the twenty-eight mansions carries such a property from the Arabic manazil tradition, used in electional and talismanic magic and transmitted to the Latin West through the Picatrix and Agrippa. These are the conventions of that tradition; the underlying stars are the twin luminaries of Gemini, Castor and Pollux, which the mansion scheme counts at this station of the Moon's monthly circuit.

Al Dhira takes its name directly from the two bright stars Castor and Pollux read as an outstretched forearm, and this mansion is among the small number of manazil, alongside Al Thurayya at the Pleiades, whose identifying stars are bright and essentially undisputed across every surviving source, in contrast to several fainter mansions where medieval Arabic star-catalogues disagree on the exact stars intended. The same twin stars anchor the Indian nakshatra Punarvasu a short distance away, another point where the two twenty-eight and twenty-seven-fold schemes fall close together without ever aligning exactly, since Al Dhira's roughly 77 to 90 degree span and Punarvasu's 80 to 93 degree 20 minute span overlap only partially.

The twenty eight mansions divide the ecliptic by the Moon rather than by the Sun, and that single choice is what makes the scheme unlike the zodiac beside it. Each mansion is exactly twelve degrees fifty one minutes wide, one twenty eighth of three hundred and sixty. Al Dhira is the seventh of them, running from 17 degrees 09 minutes of Gemini to 0 degrees 00 minutes of Cancer. The Moon's mean daily motion of about thirteen degrees eleven minutes is slightly more than one mansion, so it completes the circuit of all twenty eight in the sidereal month of twenty seven and a third days, not in the twenty nine and a half of the synodic month the phases follow.

The Arabic manazil al qamar reached Latin Europe through translation in the twelfth and thirteenth centuries, and the magical use of the mansions travelled with the astronomical scheme rather than after it. Agrippa set out all twenty eight with their degrees and their operations in the second book of the Three Books of Occult Philosophy, and that chapter, not any Arabic original, is where almost every later English language list comes from. Al Dhira is a transliteration, and the spellings vary widely between sources.

There is a problem in those degrees that the printed lists rarely flag. The mansions are named for star groups, but the boundaries above are measured in the tropical zodiac, anchored to the equinox, which drifts against the stars at about one degree every seventy two years. The Arabic scheme was fixed to the stars themselves. Something close to twenty degrees of precession has accumulated since the medieval transmission, so a mansion's tropical degrees no longer contain the stars it is named after. Both readings are in circulation and neither is a misprint.