Two charts can have the same planets in the same signs and the same houses and still describe different lives, because one was born in daylight and the other after dark. That single fact is what sect encodes.
Sect divides the seven traditional planets into two teams, a day team and a night team, and then asks which team the chart itself belongs to. Planets on the home team behave better. Planets on the visiting team behave worse. It costs nothing to check, it takes about ten seconds, and it changes how you read four of the seven planets.
The Greek word is hairesis, meaning a faction or a party, and the doctrine is cited to Hephaestio, Apotelesmatika, 1, 2: 9.
The Two Teams
Each team is led by a luminary. The Sun leads the day team, the Moon leads the night team, and the leader of the team that matches the chart is called the sect light.
The remaining planets split one benefic and one malefic to each side.
| Sect | Sect light | Benefic | Malefic |
|---|---|---|---|
| Diurnal | Sun | Jupiter | Saturn |
| Nocturnal | Moon | Venus | Mars |
| Neutral | Mercury |
Jupiter and Saturn are diurnal. Venus and Mars are nocturnal. That is the whole roster, and it does not change from chart to chart. What changes is which roster is at home.
Telling A Day Chart From A Night Chart
Look at the Sun. If it sits above the horizon, in the upper half of the wheel between the degree of the Ascendant and the degree of the Descendant, the chart is diurnal. If it sits below that axis, the chart is nocturnal.
Two caveats belong with that rule. The ancient texts generally do not specify the moment a chart switches over; the Ascendant and Descendant degree rule is Chris Brennan's rule of thumb rather than a cited doctrine. And because the sky stays light after sunset, there is ongoing debate about whether some span of degrees below the horizon still counts as day. Brennan states plainly that the range is unestablished and remains a matter of research, so a chart born within a few degrees of sunrise or sunset should be read both ways.
Day charts are covered in full at day chart in astrology, night charts at night chart in astrology.
What Sect Changes, And What It Leaves Alone
Sect is a qualitative factor, not a quantitative one. It alters the benefic or malefic character of a planet. It does not make a planet stronger, louder or more prominent. For strength you are looking at essential dignity, at angularity, at whether a planet rules the chart. Sect tells you how a planet behaves, not how much it is heard.
A planet in a chart that matches its own team is of the sect (tes haireseos), and the texts say it rejoices. A planet in the opposite kind of chart is contrary to the sect (para ten hairesin). Valens frames the contrast as whether a planet has a familiar or a foreign relation to the sect, at Anthology, 7, 2: 2.
| Condition | Benefic | Malefic |
|---|---|---|
| Of the sect | More benefic, positive significations to the forefront | Less malefic, the constructive significations brought out |
| Contrary to the sect | Moderately positive, less inclined to do good | More malefic, more problematic and potentially destructive |
The underlying principle is simple. Planets belonging to the sect of the chart tend to work in favour of the native. Planets contrary to it tend to work against the native's interests.
The Ranking That Results
Sect produces a four planet spectrum that flips depending on the chart.
| Most positive | Middle, moderate | Most negative | |
|---|---|---|---|
| Day chart | Jupiter | Venus and Saturn | Mars |
| Night chart | Venus | Jupiter and Mars | Saturn |
Stated as a working rule: the most positive planet in a day chart is Jupiter and in a night chart is Venus. The most difficult is Mars by day and Saturn by night. Brennan notes that mitigating factors can alter this, but that for the most part the rule holds despite them.
This is why the traditional labels are not fixed verdicts. A benefic contrary to sect is not delivering everything it could, and a malefic of the sect is doing something genuinely useful. The full ranking is worked through at benefics and malefics.
Mercury, Where Four Incompatible Rules Survive
Mercury is the one planet the tradition never settled, and the disagreement is not a minor variation. Four distinct rules exist, and they will hand you different answers for the same chart.
| Rule | Who held it | Citation |
|---|---|---|
| Mercury is diurnal as a morning star, nocturnal as an evening star | Ptolemy and Porphyry | Tetrabiblos, 1, 7: 1; Introduction, 4 |
| Mercury takes the sect of the planet ruling the bounds it occupies | Valens | Anthology, 3, 5: 2 |
| Mercury simply takes the sect of the chart | The Michigan Papyrus | col. viii: 19, trans. Robbins, p. 112 |
| Mercury is neutral with respect to sect | Rhetorius | Compendium, 2 |
Each has a consequence. Brennan's caveat on the first is worth keeping: it is unclear whether Porphyry is conveying Antiochus accurately or is following Ptolemy, and the parallel passage in Antiochus, Summary, 1, almost sounds as though Antiochus thought Mercury adopts the sect of whichever planet it is most closely configured with.
Valens' rule ties Mercury's sect to the bounds, so the question cannot be answered without a bounds table. The Michigan Papyrus rule, "Mercury belongs to the Moon by night and to the Sun by day," gives every chart a Mercury on the home team. Rhetorius removes Mercury from the scheme altogether.
Brennan does not resolve them. His own practical note, marked as his and not as ancient doctrine, is that Mercury's sect condition does not seem to make a major difference, since sect is primarily a modifier for the benefics and malefics, and that this may be an area requiring more research. Pick a rule, label which one, and do not pretend the question is closed.
The Two Rejoicing Conditions
Beyond team membership there are two further conditions under which a planet is said to rejoice. They are additional to sect membership rather than versions of it.
By position relative to the horizon. Diurnal planets rejoice above the horizon by day and below it by night. Nocturnal planets rejoice above the horizon at night and below it by day. So the Sun, Jupiter and Saturn prefer the top half of a day chart and the bottom half of a night chart, while the Moon, Venus and Mars prefer the top half at night and the bottom half by day. The halves are defined by the Ascendant and Descendant degrees. Valens, Anthology, 3, 5: 2.
By zodiacal sign. Here the Hellenistic tradition disagreed with itself and at least three variants survive.
- Masculine signs are diurnal and feminine signs nocturnal, so diurnal planets rejoice in masculine signs. This became the most popular variant later, perhaps through Ptolemy, who advocated it at Tetrabiblos, 1, 7: 1-2.
- The zodiac halves along the Cancer and Leo axis, with Leo through Capricorn diurnal and Aquarius through Cancer nocturnal.
- A sign takes the sect of its domicile lord, so Taurus is nocturnal because Venus rules it and Aquarius is diurnal because Saturn rules it.
The sign variant is unstable, and the instability has a name: Mars. By sect Mars is nocturnal. By the standard gender assignments, which Ptolemy gives at Tetrabiblos, 1, 6: 1, Mars is masculine. Nocturnal planets rejoice in feminine signs and masculine planets in masculine signs, so the two schemes issue Mars opposite instructions.
Brennan's Argument About Weight, And How Sect Was Lost
This is the most consequential claim in the modern literature on sect, and it is worth stating in full rather than in summary.
Brennan's position is that the rejoicing conditions, and especially rejoicing by sign, did not receive anything like the emphasis in the Hellenistic tradition that the primary consideration did. The primary consideration is simply whether the chart is day or night and which planets belong to its overall sect.
In the Medieval tradition the two rejoicing conditions were elevated to sit on par with that primary consideration. The mechanism he names is hayyiz, sometimes written hayz, a doctrine in which a planet received one point for each of the three sect conditions, and a planet scoring on all three was thought best placed. His objection, in his own words: "The problem with this scheme is that it treats all three conditions equally."
Then comes the causal claim. Brennan holds that this loss of clarity about how sect should be applied led to a decline in its usage by the seventeenth century, and that by the twentieth century sect had disappeared from the tradition completely. He suspects, in his phrasing, that the Medieval flattening "may have contributed to the decline in the use of sect," and cites Bezza, "The Development of an Astrological Term," for the concept's history.
The instruction that follows: experiment with the rejoicing conditions, but from the perspective of Hellenistic astrology the emphasis belongs on the primary condition. A three point hayz score is precisely the thing he is arguing against.
Sect At Work In A Delineation
Firmicus delineates the same placement two ways depending on sect, which shows better than any argument what the doctrine is for.
Saturn in the eighth by day allots increase in income over time, and in the domicile or terms of Mars can indicate an inheritance from the death of strangers. By night, that inheritance is lost. Mathesis, 3, 2: 16-17, trans. Bram, p. 77. Jupiter in the tenth by day makes heads of public businesses and leaders of important states, with great honours conferred. By night it makes natives honourable in character but easily cheated, with an inheritance often quickly wasted. Mathesis, 3, 3: 18-19, trans. Bram, pp. 81-82.
One textual warning. The Arabic Dorotheus at Carmen, 1, 6: 4 says Saturn harms one born by day and Mars one born at night, reversing the standard doctrine. Brennan judges it a scribal error, since the same book states the rule correctly at 1, 7: 23-4 and at 1, 26: 29.
Frequently Asked Questions
What Is Sect In Astrology In One Sentence?
Sect is the division of the seven traditional planets into a day team led by the Sun and a night team led by the Moon, combined with the question of whether the chart itself is a day or a night chart.
What Is The Sect Light?
The sect light is the luminary leading the team that matches the chart. In a day chart it is the Sun. In a night chart it is the Moon.
Does Sect Make A Planet Stronger?
No. Sect is a qualitative factor that changes how benefic or malefic a planet behaves. It is not a quantitative factor and does not alter how strong or prominent a planet is in the chart.
Which Sect Is Mercury In?
There is no settled answer. Ptolemy and Porphyry make it depend on whether Mercury is a morning or an evening star, Valens makes it depend on the ruler of the bounds Mercury occupies, the Michigan Papyrus has Mercury take the sect of the chart, and Rhetorius calls Mercury neutral.
What If I Was Born Right At Sunrise Or Sunset?
The switch point is genuinely unsettled. The Ascendant and Descendant degree rule is a modern convention, and the twilight range below the horizon has never been established. Read a borderline chart both ways.
Should I Use A Hayz Score?
Brennan argues against it, on the grounds that awarding one point each to sect membership, hemisphere and sign treats three unequal conditions as equal. Sect membership is the rule and the other two are refinements.
Recommended Reading
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- Chris Brennan, Hellenistic Astrology: The Study of Fate and Fortune (2017), for the structure of the doctrine, the four planet ranking, the rejoicing conditions, and the argument about hayyiz and the decline of sect.
- Hephaestio, Apotelesmatika, 1, 2: 9, on the division into two sects, and 1, 2: 10 on planetary gender.
- Ptolemy, Tetrabiblos, 1, 7: 1-2 on Mercury's phase rule and on rejoicing by masculine and feminine signs; 1, 6: 1 on planetary gender.
- Porphyry, Introduction, 4, on Mercury's phase rule.
- Valens, Anthology, 3, 5: 2 on Mercury and the bounds and on the hemisphere condition; 7, 2: 2 on familiar and foreign relation to the sect.
- Michigan Papyrus, col. viii: 19, trans. Robbins, p. 112, on Mercury taking the sect of the chart.
- Rhetorius, Compendium, 2, on Mercury as neutral.
- Firmicus, Mathesis, 3, 2: 16-17 and 3, 3: 18-19, trans. Bram, for the sect delineations.
- Dorotheus, Carmen, 1, 7: 23-4 and 1, 26: 29, for the rule stated correctly.
- Bezza, "The Development of an Astrological Term," cited by Brennan for the history of the concept.
Continue Learning
Next: Day Chart in Astrology and Night Chart in Astrology, then Benefics and Malefics in Astrology. For where the whole scheme comes from, see The Thema Mundi, and for the other place sect enters a judgement, Mutual Reception.