Semisextile Meaning in Astrology

Inez has Mercury at 17 degrees Leo and Venus at 18 degrees Virgo, 31 degrees apart, a semisextile with a 1-degree orb between signs that share neither element nor modality.

A semisextile is an angle of 30 degrees between two chart points: one twelfth of the circle, or exactly one sign. The bodies usually sit in neighboring signs, and the common orb is about 1 to 2 degrees, tighter than for any of the five major aspects.

It is a minor aspect. Many astrologers leave it out of a reading unless it involves a luminary, the chart ruler or an angle. Others include it as a note about two areas of life that sit next to each other but do not speak easily.

Convert each position to a number from 0 to 360, subtract, and compare the gap with 30.

1. Venus at 28° Pisces is 330 + 28 = 358. Mercury at 29° Aries is 0 + 29 = 29.
2. Subtract: 358 − 29 = 329. Because that is more than 180, take 360 − 329 = 31.
3. Subtract 30. The orb is 1 degree, so the pair is a semisextile.
4. Check the signs. Pisces and Aries are neighbors, so the signs agree with the degrees.

A shortcut follows from the arithmetic: two bodies at the same degree number in adjoining signs are exactly 30 degrees apart, such as 29° Aries and 29° Taurus. The trap runs the other way. A planet at 29° Aries (29) and another at 1° Taurus (31) are in neighboring signs but only 2 degrees apart. By degrees that is a conjunction, not a semisextile, even though the signs differ.

Neighboring signs always differ in both element and modality, which is why the pair can feel like strangers on the same street. The table gives the step from each sign to the next.

In traditional astrology neighboring signs are in aversion: they do not see each other, so the 30-degree angle was not an aspect. Johannes Kepler added it to the minor angles in the early seventeenth century.

Modern readers describe it as a link between two things that belong in the same story but do not understand each other naturally. It is the weakest of the connecting angles, so it usually shades a reading rather than leading it.

Any pair can be semisextile. A few are worth noting.

• Mercury and Venus: both stay close to the Sun, so they are often within a few signs of each other, and a 30-degree gap is common. Speech and taste are neighbors that may not coordinate.
• Sun and Moon: the Sun and Moon 30 degrees apart means a Moon about two and a half days from the new Moon. Will and need are close but unfamiliar to each other.
• Venus and Mars: attraction and pursuit are one sign apart, a pair that may take a moment to line up.
• Jupiter and Saturn: expansion and limits sit next to each other, which can show up as a question about pace.

Inez is constructed. Her Mercury is at 17° Leo, which is 120 + 17 = 137, and her Venus at 18° Virgo, which is 150 + 18 = 168. The gap is 31 degrees, a 1-degree orb. Leo is fire and fixed, Virgo is earth and mutable, so they share neither.

A reader might say that her speech has Leo’s warmth and flourish, while her taste has Virgo’s precision and restraint. She may enjoy a big gesture and then trim it. The aspect points to a small, familiar tension rather than a theme that dominates. A report that counts only major aspects would not list it, which is why a reader should state the policy.

Most people never notice one. It feels like a neighbor you pass every day without knowing well: two parts of you that sit side by side, are aware of each other and still run on different habits. You may only see it when you ask why a pair of interests or traits never seems to coordinate.

It is rarely the main storyline. If it matters at all, it tends to matter as a small, familiar friction that repeats the same theme as a stronger contact elsewhere in the chart.

There is no right answer, only a consistent one. Pick before you read and tell anyone you share the chart with.

1. Leave minor aspects out and read the major five only.
2. Include a semisextile only when the orb is 1 degree or less.
3. Include it only when it involves the Sun, Moon, Ascendant or chart ruler.

Does a semisextile mean anything on its own? Rarely. It becomes useful when it repeats a theme found elsewhere in the chart, such as two planets that are also in neighboring houses.

Is it good or bad? It is neither. It describes proximity without natural understanding.

Why is the orb so small? The angle is minor, and pairs of bodies within a sign or two of each other are everywhere in a chart. A wide orb would flag most of them and bury the aspects that stand out.

Is a semisextile the same as two planets in neighboring houses? Not quite. In whole-sign houses planets in neighboring signs are in neighboring houses, but the aspect also depends on the degrees, so one can exist without the other.

A semisextile rarely means much on its own, and a report counting only major aspects will not list it, so state your policy.