Houses & Aspects

A birth chart is divided into 12 sections called Houses. If planets are the actors and signs are their costumes, the Houses are the stages where the action takes place.

For couples, three houses are particularly important:

The 5th House: Romance, playfulness, creativity, and pleasure.
The 7th House: The primary house of committed partnerships, equality, and marriage.
The 8th House: Deep intimacy, shared resources, and psychological transformation.

Aspects are the specific geometric angles that planets form with one another. These angles are the mathematical foundation of everything you see on the StellarTies dashboard.

Conjunction (0°): Planets occupy the same position, blending their energies into intense, unified focus.

Sextile (60°): A highly supportive angle that provides opportunity, compatibility, and ease of communication.

Square (90°): An angle of friction and tension. While challenging, squares are highly energizing and represent areas where a couple is forced to evolve. This geometry directly powers the Growth score.

Trine (120°): An angle of supreme harmony and natural ease. Trines indicate areas where partners understand each other without effort. This drives high Flow scores.

Opposition (180°): Planets sit across from each other, creating a mirror-like push-pull polarity that requires conscious balance.

Quincunx (150°): Two energies that don't naturally "see" each other, requiring continuous adaptation.

Aspects are rarely exact to the degree. The allowable margin of error is called an orb. A tighter orb means a more powerful connection.

Tight orbs (0°–2°): Core dynamics that define the relationship.
Medium orbs (2°–5°): Significant influences that shape the overall tone.
Wide orbs (5°–8°): Background flavors — felt but not primary drivers.

StellarTies uses an orb-weighted scoring system where tighter aspects receive more weight. Personal planet pairs get wider orbs than outer planet contacts, reflecting their stronger felt impact.

Before the houses come the four angles — the chart's spatial skeleton. They are not signs or planets but geometric anchor points: the two places where the ecliptic crosses the horizon, and the two places where it crosses the local meridian.

The Ascendant (ASC): the eastern horizon at the moment of birth, and the cusp of the 1st house. It governs self-presentation — the mask you wear, the way you arrive in a room, even the physical body. Your rising sign is the sign on this point.

The Descendant (DC): the western horizon, exactly opposite the ASC, and the cusp of the 7th house. This is the partner axis. The DC describes what you instinctively seek in a mate and what you project onto them — the qualities that feel magnetic precisely because they sit across from your own self-image. After the Sun-Moon-Venus-Mars complex, no point in the chart is more load-bearing for relationship astrology.

The Midheaven (MC): the highest point the ecliptic reaches that day, and the cusp of the 10th house. It describes your public role, your career direction, what you are known for.

The Imum Coeli (IC): directly below the MC, the cusp of the 4th house. Roots, family of origin, the private home — and, in a partnership, the inner life two people build together.

In synastry, the DC is where chemistry hides in plain sight. When your partner's Sun or Venus falls on your Descendant, the "I see what I have been looking for" recognition is structural, not coincidental.

The 12 houses above describe what the houses mean. A fair follow-up question — one savvy users ask — is how the cusps are drawn. Multiple house systems exist (Placidus, Whole Sign, Equal, Koch, Porphyry, Regiomontanus), and they place the cusps at different degrees. StellarTies uses Placidus.

Placidus, devised by the Italian monk Placidus de Titis around 1650, is the most widely used system in modern Western astrology and the dominant choice in the psychological-astrology lineage StellarTies builds upon. It is a time-based method: it divides the diurnal arc — the Sun's path from rising to setting — into equal segments of time, which produces houses of unequal size in space. The trade-off is deliberate. Because the system is anchored to the Sun's daily motion, the four angles (ASC, DC, MC, IC) are always exactly the cusps of the 1st, 4th, 7th, and 10th houses. Those four points carry real interpretive weight, and Placidus keeps them load-bearing.

The geometry breaks down above the Arctic and Antarctic Circles, where the Sun can fail to rise or set on a given day; for births in those latitudes we surface a polar warning rather than return a misleading cusp.

Whole Sign houses — the oldest system, recovered from Hellenistic sources — assign each house to exactly one sign, simpler but with looser angle-cusp coupling. It is well worth exploring, but the choice belongs to a different lineage than the one our interpretations are tuned to. The precision ephemeris behind your chart calculates the Placidus cusps to the arc-second.

There are two zodiacs, and Western astrology uses the one that no longer matches the constellations.

The tropical zodiac is the one StellarTies and most Western astrology use. It divides the ecliptic into 12 equal 30° slices, measured from the vernal equinox — the point where the Sun crosses the celestial equator each spring. The first slice begins at 0° Aries and ends at 30°. The next is Taurus. And so on around the circle. The signs are tied to the seasons, not to any particular star.

The sidereal zodiac, used in most Vedic astrology, anchors instead to the actual fixed-star constellations. When the two systems were first aligned — roughly two millennia ago — the difference between them was nearly zero. Today it is not.

The reason is precession of the equinoxes. Earth's axis wobbles slowly, like a spinning top, completing one full circle every ~26,000 years. The vernal equinox drifts westward against the background stars at about 50 arcseconds per year — roughly one degree every 72 years. Over the ~2,200 years since the tropical zodiac was anchored, the drift has accumulated to roughly 24°.

Concretely: the tropical sign of Leo runs from ecliptic longitude 120° to 150°. But the bright star Regulus — the heart of the constellation Leo, the lion's chest — currently sits at longitude ~150°. That is the very first degree of the tropical sign of Virgo. The lion's heart has slipped across the line into the next sign over.

The constellations themselves do not help. They are wildly uneven: Virgo spans about 40° of sky, Cancer barely 20°. Even with no precession at all, 12 equal 30° slots could never line up neatly with constellation outlines.

So why does StellarTies (and Western astrology more broadly) stay with the tropical zodiac? Because the system was never really about the stars. It was built around the relationship between the Earth and the Sun — the equinoxes, the solstices, the turning of the seasons. Aries is not "where the constellation Aries is"; it is "the quality of the year right after the vernal equinox." That symbolism is seasonal, and it does not drift.

If you want to see this for yourself, open the live sky dome and toggle the constellation lines on. Watch the planets' tropical sign chips against the actual outlines of the star groups behind them — you will see Regulus and the lion sitting comfortably inside the tropical Virgo chip, Spica well into Libra, Antares deep in Sagittarius. The chart and the sky are using two different rulers. Both are valid; we have simply chosen the seasonal one. For more on why a single Sun sign — in either zodiac — explains less than people assume, see Beyond Sun Signs.

Individual aspects tell partial stories. A single square might look alarming in isolation, but when supported by trines and sextiles in related areas, it often becomes a source of productive chemistry rather than conflict.

The power is in synthesis: seeing how all aspects interact, which themes dominate, and how they balance. StellarTies organizes this into four clear dimensions and then uses expert-curated interpretation to translate the geometry into actionable insight.