Conjunction aspect: two bodies at the same degree

In the Tetrabiblos (book I, chapter 13), Ptolemy defines the aspects as relationships between signs separated by a set distance: the opposition (six signs, 180°), the trine (four signs, 120°), the square (three signs, 90°) and the sextile (two signs, 60°). The conjunction is not among them: two bodies in the same sign are separated by no interval at all.

William Lilly, in Christian Astrology (1647, book I, chapter XIX), says it plainly: we are used to calling the conjunction an aspect, “but very improperly.” He defines it as the meeting of two planets “in one and the same degree and minute of a sign,” and notes that it is also called coition, synod or congress. On its quality, his rule fits in one sentence: conjunctions are good or bad as the planets joined are friends or enemies to one another.

Lilly's rule remains the key to reading it. The conjunction has no color of its own: it creates neither friction like the square nor ease like the trine. It fuses two functions, which stop acting each on its own and form a single impulse, concentrated in one sector of the chart. The legend that precedes the aspect table in your report sums it up in one word: fusion.

To read it, do not comment on each body separately. Ask yourself what becomes of the two functions once they act as one. With the Sun and the Moon together, conscious will and emotional need merge: you tend to want what you feel and to feel what you want, which gives great coherence or, depending on the rest of the chart, difficulty telling one from the other. The sign and house where the conjunction sits then tell you on what ground this fusion plays out.

For Lilly, the tolerance depends not on the aspect but on the planets. Each body radiates an orb around itself, and two planets are in aspect when they are closer than half the orb of one plus half the orb of the other. His table gives 17° to the Sun, 12°30' to the Moon, 12° to Jupiter, 10° to Saturn, 8° to Venus, 7°30' to Mars and 7° to Mercury, noting that other authors use smaller values. In one of his examples, where he grants 9° to each, Jupiter is fully separated from Saturn only at 9° apart: half of each orb, 4°30' and 4°30'.

AstralPro works differently: the orb of the conjunction is 8°, the same for all bodies, luminaries included. Two bodies 0° to 8° apart are in conjunction; beyond that, the aspect is not kept. This table of orbs by aspect serves both the birth chart and the Book, so that the two never list different aspects for the same chart.

In chapter I, “The complete aspect grid” lists every admitted aspect, ranked from tightest to widest, with its orb in degrees and minutes. The name of the conjunction appears there in gold. The Direction column says whether it is applying (the two bodies are moving closer), separating (they are moving apart) or exact; it carries a dash when an angle is involved or both bodies are slow. The Reading column comments on the lines up to 3° of orb, at least twenty and at most thirty.

The wheel is more selective: it draws a conjunction only at 5° or less, between the ten planets, the Ascendant and the Midheaven, and never between two of the three slow planets, Uranus, Neptune and Pluto. Those pairs are also left out of the aspects the chapters discuss: a whole generation shares them.

For Camille Morel, AstralPro's sample chart (fictional data), the grid of 40 aspects counts thirteen conjunctions, and it opens with one of them: Mercury conjunction Venus, orb 0°07', Applying. Mercury, retrograde at 6°37' Scorpio, is moving back toward Venus at 6°30'. It is the tightest aspect in the chart, drawn on the wheel, discussed in chapter I and taken up in the Friendships & social life domain.

The second line is also a conjunction, but of another order: Uranus and Neptune, at 19°10' and 18°56' Capricorn, orb 0°15'. Two slow planets: the Direction column carries a dash, the wheel does not draw it, and no chapter discusses it, because everyone born in those years has it.

Next come Mars conjunction North Node (0°37', Separating, Inner climate section), Moon conjunction Pluto (1°52', Separating, Shadow side section), Sun conjunction Pluto (3°23', Applying, Anger & reaction section), then Sun conjunction Moon (5°15'), and Venus and Mercury conjunction Jupiter (5°40' and 5°47').

Two conjunctions straddle a sign boundary. The Moon, at 27°09' Scorpio, joins Mars at 3°38' Sagittarius (6°29', Applying, discussed in chapter I). And the grid closes on Pluto conjunction North Node, at 7°43', right at the edge of the 8° limit. AstralPro counts in degrees: the change of sign does not prevent the conjunction, but it shades its color.

A conjunction to the Sun is not quite like the others: the planet is lost in its light. From this, tradition drew combustion and cazimi, which AstralPro calculates separately, with their own thresholds. For Camille, Pluto is 3°23' from the Sun: the grid shows the conjunction, and the dignity data flag Pluto as combust. The report reads the two facts together, as a Pluto in domicile acting in the Sun's shadow rather than in the open.

The conjunction of the Sun and the Moon also has a double: the lunar phase. At 5°15', Camille's Moon has just left the Sun, and her report names her natal phase New Moon. The conjunction appears in the grid, with no reading of its own beyond 3°, and the phase takes it up from another angle.

Finally, a series of conjunctions in one sign is not a stellium. Jupiter, at 0°50' Scorpio, and the Moon, at 27°09', belong to the same stellium without being conjunct: more than 26° separate them.