How the old astrologers told a day chart from a night chart

The old texts sort the seven planets into two teams. The Sun, Jupiter and Saturn belong to the day. The Moon, Venus and Mars belong to the night. Mercury goes with one team or the other, and Ptolemy and Valens attach it by different rules. A day chart is a chart for a birth by day, and in it the day team is in its own sect. A night chart is a chart for a birth by night, and the night team is in its own sect. Both authors treat the team a planet belongs to as something that changes how it acts. The rest of this piece sets out what each says, where they differ, and where they say nothing.

The two teams

Mercury is the exception. Ptolemy makes it of the day when it is a morning star and of the night when it is an evening star. Valens makes it follow the sect of the ruler of the terms it stands in. Both authors give the day and night teams: Ptolemy in Tetrabiblos I.7 and Valens in Anthology I 1. Valens gives no Mercury sect in I 1; his Mercury rule is in III 5.

What makes a chart a day chart

Ptolemy in I.7 and Valens in III 5 treat day and night as given. Valens writes of “day births” and “night births” throughout and does not define them. The old texts I read do not state a rule for telling one from the other. Modern authors do: a chart is a day chart when the Sun is above the horizon and a night chart when it is below (Brennan, Hellenistic Astrology, p. 192; George, Ancient Astrology in Theory and Practice, Vol. I, pp. 74–75). Brennan reports that cases near sunrise and sunset are unsettled (p. 192).

Those authors take the horizon to be the exact line from the Ascendant degree to the Descendant degree (George, Vol. I pp. 74–75; Brennan pp. 195–196). The old texts I read do not say. A chart becomes a day chart once the Sun reaches and rises above the exact degree of the Ascendant (Brennan, p. 192). I use whole-sign houses, and that sits alongside the horizon test because the two do different jobs: whole-sign houses name the sign each house holds, and sect follows the horizon.

Ptolemy’s lists and his reason

Ptolemy gives the lists in I.7 and a reason for them. In Robbins’s translation, “the tradition has consequently been handed down that the moon and Venus are nocturnal, the sun and Jupiter diurnal, and Mercury common as before, diurnal when it is a morning star and nocturnal as an evening star” (Ptolemy, Tetrabiblos I.7, trans. Robbins, p. 43).

His reason runs through the four qualities (hot, cold, moist, dry), which I take up in the article on temperament. In Ashmand’s translation (first published in 1822), which follows Proclus’s paraphrase of the Greek:

The day and the night are the visible divisions of time. The day, in its heat and its aptitude for action, is masculine:—the night, in its moisture and its appropriation to rest, feminine.

(Ptolemy, Tetrabiblos I.7, trans. Ashmand, p. 15)

The Sun and Jupiter go with the day and the Moon and Venus with the night on that ground. Saturn and Mars, the two Ptolemy calls destructive, he places by the opposite rule. Ashmand renders it this way:

Neither of them, however, is allotted to that division of time with which its nature accords (as heat accords with heat), but each is disposed of on a contrary principle: and for this reason, that, although the benefit is increased when a favourable temperament receives an addition of its own nature, yet, the evil arising from a pernicious influence is much mitigated when dissimilar qualities are mingled with that influence. Hence the coldness of Saturn is allotted to the day, to counterbalance its heat; and the dryness of Mars to the night, to counterbalance its moisture.

(Ptolemy, Tetrabiblos I.7, trans. Ashmand, p. 15)

So in Ptolemy’s account Saturn is cold and placed with the warm day, and Mars is dry and placed with the moist night. He gives no rule in I.7 for what happens when a planet is placed above or below the horizon. He does use sect elsewhere. In III.2, on finding the rising degree, he says that when two or more planets are close in claim the astrologer follows “the one which is most nearly related to the centres and the sect” (Ptolemy, Tetrabiblos III.2, trans. Robbins, p. 233).

Valens: sect and position

Valens adds position. In III 5 he writes: “for day births the Sun, Jupiter, and Saturn rejoice above the Earth; for night births, below the Earth” (Valens, Anthology III 5, trans. Riley, p. 128). The night team, the Moon, Mars and Venus, is the other way about: they rejoice above the Earth for night births and below it for day births. He says that in a day birth Jupiter, the Sun or Saturn well placed above the Earth is better than the same planet below it, and the same holds for the night team in a night birth. Venus, he says, rejoices most in the Ascendant or at the Midheaven, and the others in the Ascendant or Descendant.

Valens also says the team matters for the planets the tradition calls harmful. In II 2 he writes that when they are “configured properly, in their own sects,” Saturn and Mars are not to be taken as harmful in every case: “they can be bestowers of good” (Valens, Anthology II 2, trans. Riley, p. 52). In his account the same planet out of its own sect can bring the opposite.

The sect lords of the triplicities

The same idea sorts the rulers of the four triangles of signs into day lords and night lords. Valens, in II 1, begins from it: “we find two sects, solar and lunar, day and night” (Valens, Anthology II 1, trans. Riley, p. 49). Dorotheus gives the lists in I.1. The table below is my own arrangement of the order each author gives.

For the earth, air and water triangles Valens, in II 1, gives the same order as Dorotheus. For the fire triangle he names the Sun as lord by day and Jupiter by night and says Saturn “works with both”; he does not state the full three-place order there. Dorotheus adds that in Virgo there is also a share for Mercury. Ptolemy gives a day lord and a night lord for fire, earth and air. For water he gives Mars, with the Moon by night and Venus by day as co-rulers. He has no third lord of the Dorotheus kind.

Where the sources differ or are silent

Mercury. Ptolemy decides by morning or evening star. Valens decides by the sect of the ruler of the terms Mercury is in. The two rules can give different answers for the same chart. Valens, in II 1, also calls Mercury “common” and says it works with both sects.

Position. Ptolemy’s I.7 says nothing about above or below the horizon. Valens’s “rejoice” language in III 5 is about exactly that.

Saturn and Mars. Dorotheus, in I.6, has a line that appears to cut against the others: “Saturn harms one who is born by day and Mars one who is born at night” (Dorotheus, Carmen Astrologicum I.6, trans. Pingree). It puts each of these two against its own sect, where Valens, in II 2, speaks of them doing well in their own sect, and where Ptolemy’s reasoning in I.7 pairs cold Saturn with the warm day. Brennan calls the line an error in the Arabic text and says the rule is stated correctly at I.7 and I.26 (Brennan, Hellenistic Astrology, p. 199, note 202). In I.26 Dorotheus writes: “If by day Mars is with the lord of the lot of fortune or aspects it from quartile or opposition, then there is no good in it” (Dorotheus, Carmen Astrologicum I.26, trans. Pingree, Teubner p. 191). That is Mars harmful by day. The judgment that I.6 is an error in the Arabic text is Brennan’s; the text of Dorotheus does not show it by itself.

Sect of the lights. In Dorotheus I.4 the lord of the triplicity of the Lot of Fortune is called good if it is aspecting the Lot or in a good place and “aspecting the Sun by day or the Moon by night” (Dorotheus, Carmen Astrologicum I.4, trans. Pingree). The sentence is about that one lord, and it names the Sun as the light that matters by day and the Moon by night.

Translation. Ashmand’s translation follows Proclus’s paraphrase of Ptolemy. Where he and Robbins word a passage differently I have said so; on the lists of planets they agree.

What this does not cover

This piece does not give a calculator or a way to compute a chart. It does not cover the later developments of sect, such as how much weight each author gives it in a full judgment of a chart, or sect in the work of authors I have not read for this piece (Firmicus, Paulus). It does not judge any person’s chart.