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Secrets of the Three-Day Moon in Astrology

If you read my last blog post on the Magic of Triplicity Rulers in Astrology, then you’ll recall our introduction to Dorotheus of Sidon, the first-century astrologer whom A. Wasserstein, reviewing David Pingree’s 1976 translation of Carmen Astrologicum, called “immensely influential among Persian, Arabic and Byzantine astrologers of late antiquity and the middle ages” (1). While Ben Dykes advances an argument for the writing of Carmen in the early second century, we can generally assume that Dorotheus’ text was at least in circulation at the time that the famous astronomer, Claudius Ptolemy, was observing the heavens.

Ptolemy’s Tetrabiblos is widely regarded as one of the most influential — if not the most influential — text in the history of Western astrology. Alongside the Almagest and the pseudonymous Centiloquium, these texts contributed to the standard corpus of astrological learning in the Medieval academy, supplemented by Aristotelian and Galenic material. Mark Riley makes an interesting observation concerning Ptolemy’s astrological writing:

“Reviewing…the differences between Ptolemy on the one hand and Dorotheus, Valens, Haphaistion, and Firmicus on the other, one can clearly see the great astronomer’s detachment from the professional concerns of the typical astrologer and his emphasis on the theoretical and universal aspects of astrology” (2).

Riley contends that Ptolemy omitted various techniques and procedures known to practicing astrologers of the period, including approaches for elections and interrogations (3). For those looking to pick up a few techniques from the ancients, Tetrabiblos is hardly the text by which to accomplish this; instead, this tome “[outlines] the theoretical basis for the…power which the celestial bodies have over the earth” (4), but stops short of being truly useful to the astrological practitioner. Indeed, as Riley concludes, “The respect shown Ptolemy’s work by all later astrologers was due, not to its usefulness to the practitioner, but to the magisterial synthesis of astrology and science” (5). Ptolemy is the text to understand the theoretical basis for “prediction through astronomy,” while writers like Valens and Dorotheus provide practical methods for synthesis and interpretation, more akin to what we expect an astrological “cookbook” to include.

A brief technique that piqued my curiosity was Dorotheus’ consideration of the Moon on the third day from birth for forecasting the overall condition of the native’s life (6). In this technique, Dorotheus invites us to consider the sign that the Moon is in on this day, its exaltation lord, any planets co-present with it, the condition of the sign ruler, and any planets aspecting it. Additionally, the condition of the lord of the house that the Moon is in and its bound ruler are also important since these can help the astrologer arrive at a more comprehensive judgement (7).

Dorotheus also introduces consideration of the Moon’s twelfth part (dodekatemoria), which is not something often encountered in most texts on natal delineation and for which I have found the approach contemplated in Paulus Alexandrinus and Olympiodorus most helpful (8). I abhor complex math, so while I have noted various criticisms of Paulus’ approach, the simple multiplication of the degree of the star or pivot point we are contemplating by the 13 has saved me a world of arithmetical pain and I use it frequently. To find the third-day Moon’s twelfth part, multiply the whole degree of the Moon by 13 and locate this point on the chart. Similar to all the considerations noted earlier, we should look to see whether any planets aspect this point, particularly benefics or malefics, what house it is in, the condition of its ruler, and so forth. In a different technique I picked up on the twelfth-part of the ascendant, which gets treated like a sensitive point in the chart, susceptible to transits in particular, I can’t help wondering whether the third-day Moon’s twelfth-part has any similar sensitivity.

Dorotheus also examines the phase the Moon is in and its hemispheric location. He notes that a waxing Moon, “rising up in the circle of heaven up toward the direction of the north…is a mark of blessings and manliness for the native” (9). A waxing Moon is preferable in all scenarios, with it either being in the north of the chart or crossing over to it; it appears that the southern hemisphere is less desirable.

Finally, one additional consideration for the third-day Moon is the tenth place from it. Dorotheus instructs us to look at this place as any benefics found there can “[indicate] splendor and goodness,” whereas malefics…well, you can imagine what they might mean! All standard delineations apply! I assume that the tenth place, given its typical association with esteem, public standing, accomplishments and the zenith point, is the reason why we contemplate it in relation to the overall condition of the native. The Moon, in general, also has an association with things that are more temporal — things that come into being, pass away and change, much like our fortunes, or the Moon’s waxing and waning cycle.

So, there we have it — a brief but instructive technique for further dissecting the natal Moon. I gave this a try and, in very broad strokes, arrived at an assessment not dissimilar from what my chart suggests when individual houses, like the second, tenth, and eleventh are assessed for their natal promise.

Let me know if you give this technique a try, and don’t forget to follow me on IG: @theeclecticoccultista.


(1) A. Wasserstein, “Review of Dorothei Sidonii Carmen Astrologicum, by Dorotheus of Sidon & David Pingree,” The Classical Review, 28.2 (1978), 385. [accessed May 28, 2022]

(2) Mark Riley, “Theoretical and Practical Astrology: Ptolemy and His Colleagues,” Transactions of the American Philological Association (1974-), 117 (1975), 235–256 (pp, 254–255). [accessed May 28, 2022]

(3) Ibid., p. 236.

(4) Ibid., p. 254.

(5) Ibid., p. 255.

(6) Dorotheus of Sidon, Carmen Astrologicum: The ‘Umar al-Tabari Translation, trans. and ed. by Benjamin N. Dykes (Minneapolis: The Cazimi Press, 2019), p. 77.

(7) Ibid.

(8) Late Classical Astrology: Paulus Alexandriunus and Olumpiodorus with the Scholia from Later Commentators, trans. by Dorian Gieseler Greenbaum (Reston, VA: Arhat, 2001), pp. 40–41.

(9) Dorotheus of Sidon, Carmen Astrologicum, p. 78.

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