The semi-sextile is the 30-degree angle between two points in the chart, the exact distance from one sign to the next. If your Sun is in Aries and your Venus is in Taurus, with only a few degrees between them within the signs, you have a semi-sextile.

It is a aspect minor one: tradition keeps the name major for the conjunction, the opposition, the trine, the square and the sextile. Minor does not mean weak, it means tight orb, it only counts when the angle is nearly exact.

And it has a feature no other aspect has, one that explains the rest of this page: neighbouring signs share nothing. Aries is fire, cardinal and assertive; Taurus is earth, fixed and receptive. There is no element in common, no modality, no polarity. It is the only angle in the chart where the two sides do not even have a starting point for the conversation.

I drew 200 thousand charts between 1930 and 2025, with the same ephemeris and the same orbs this site uses to build yours, and I counted the semi-sextiles among the ten planets.

On average, there are 0.73 semi-sextiles per chart; 51.1% of charts have at least one; the most common pair, Sun and Venus, has 5.6%; and the second, Mercury and Venus, 5.0%.

A little over half of people have one. It is the aspect that sits right on the border between common and uncommon, and that is why it deserves a page: whoever generates a chart on this site sees the word on screen in half the cases, and had nowhere to read what it means.

Notice who leads the list: Sun and Venus, then Mercury and Venus. It is not coincidence, it is geometry. Venus never moves more than 47.2 degrees from the Sun and Mercury never more than 27.8, the three of them live crowded into the same patch of sky, so the chance of landing 30 degrees apart is much higher than for two planets on their own.

And that same chain produces the loveliest finding on this page. Sun semi-sextile Mercury is impossible, and it misses by very little.

The greatest distance from Mercury to the Sun, measured from 1930 to 2025, is 27.8°; the minimum the semi-sextile requires, with a 2° orb, is 28.0°; and 0.2° is missing.

Two tenths of a degree. In 200 thousand charts drawn, zero. Mercury comes close every year and never crosses the line, because its orbit is small and, seen from Earth, it stays tied to the Sun's light.

This has a practical consequence worth keeping in mind: if some program shows you a Sun semi-sextile Mercury, the calculation is wrong. It is the same kind of check that applies to "Sun square Mercury", which also does not exist and for the same reason, except the square misses by 62 degrees and the semi-sextile misses by two tenths.

On this site the semi-sextile counts with 2 degrees when it involves the Sun or the Moon, 1.5 degree for Mercury, Venus, Mars, Jupiter and Saturn, and 1 degree for Uranus, Neptune and Pluto. For comparison: the conjunction with the luminaries allows 10 degrees.

The reason has to do with measurement, and it can be put simply: a minor aspect with a wide orb shows contact in almost every chart, and an aspect that appears always stops saying anything. With the orbs above, the semi-sextile shows up in half of people. If the orb doubled, it would show up in almost everyone, and the word would lose its use.

The smaller orb for the slow planets has another reason still: Uranus, Neptune and Pluto move so slowly that they stay at the same degree for weeks. A wide orb on them would describe an entire generation, not a person.

In a reading, the semi-sextile is an aspect of adjustment. The two points do not clash, as in a square, and do not help each other, as in a trine: they simply do not understand each other at first, because they have nothing in common to start from.

In practice it tends to show up as a discomfort the person cannot name. A square brings a fight, and a fight is easy to point to. A semi-sextile gives that sense that two parts of you work on different schedules, and since there is no visible friction, nobody looks into it.

Three things it tends to describe:

• A resource sitting right there, unused. The next sign has exactly what the one before it lacks, and closeness gets in the way instead of helping.
• A small, constant adjustment. Nothing dramatic, and nothing that gets resolved all at once.
• The passage from one cycle to the next. Thirty degrees is the distance between the end of one sign and the start of the next, and a semi-sextile in the chart marks that joint.

And the honest limit: at 0.73 per chart, the semi-sextile is almost never the main subject of a reading. It is detail, and detail carries weight only after the big pieces have already been read, the Sun, the Moon, the Ascendant and the major aspects.

And the questions that come up most on this subject, with the short answer: