Synastry orb scale

Synastry orb scale

When you compare two charts for compatibility — yours and someone else's — the aspect detection has to decide which connections between the two of you count and which don't. The same aspect (Sun trine Moon, say) is "real" only if the two planets are close enough in angle to the exact aspect distance. The threshold for "close enough" is an orb, and how wide you set it makes a large practical difference in how a compatibility chart reads.

Why synastry orbs are usually halved

In a single natal chart, aspect orbs are typically generous. A conjunction might count at up to 8°, a trine at 6°, a sextile at 4°. These ranges work because in a single chart, the aspects are between the same person's planets — Sun and Moon are working with each other for an entire lifetime, and even a wider angle still creates a felt influence over decades.

In synastry — two people's planets aspecting each other across the boundary — most practitioners halve these orbs. The conventional starting point:

• Conjunctions and oppositions: 6-8° → 4-5°
• Squares and trines: 6-7° → 3-4°
• Sextiles: 4° → 2-3°
• Minor aspects: 2-3° → 1-2°

The rationale: synastry contacts come and go with the relationship itself, not with the people. A planet at 8° away from exact contact with someone else's planet might feel like a faint background hum at best; at 3° it actually plays in the room. Halving the orbs cuts out the background noise and surfaces the contacts you'd actually feel.

This is also why most compatibility software defaults to tighter orbs for synastry. The synastry charts that come out of "natal orbs" tend to feel cluttered — too many aspects, no clear story.

What the scale knob does

The synastry orb scale is a single multiplier applied to every synastry orb. The default of 1.0 uses StarBind's base synastry orbs — already the halved ones, not the natal-sized ones. Values above 1.0 widen the orbs (more aspects qualify); values below 1.0 narrow them (fewer aspects qualify, but each one is tighter).

The sensitivity-vs-noise trade-off

Tighter orbs give you a higher-signal chart — fewer aspects, each one tightly connected, each one carrying real weight. The risk: you miss the soft-but-present contacts that genuinely shape a relationship.

Wider orbs give you a more-complete chart — more aspects, including subtle ones — but the risk is that the strong contacts get drowned out by background noise. A reading that mentions 47 synastry aspects is harder to learn from than one that mentions 12.

For most users, the default of 1.0 is the right starting point. The reasons to move it:

• Cluttered output: every aspect you read about feels generic. Lower the scale to 0.7 or 0.5 to keep only the tight contacts.
• Feels too sparse: a relationship that you know is intense produces a flat synastry chart with two or three lukewarm contacts. Raise to 1.2 to surface near-misses.
• Aspect grade testing: you're studying which orbs actually correlate with felt experience in your own relationships. Move the scale and observe.

What it doesn't change

The orb scale is multiplicative on the orbs, not on the aspects themselves. The angles (0°, 60°, 90°, 120°, 180°) don't shift. Your sextile is still a sextile; the orb just decides whether two planets count as sextiling. You can't, for example, use the orb scale to add quincunxes or quintiles to the analysis — that's controlled by a separate knob.

Likewise, the scale doesn't change the orb weighting — how much a tight aspect "counts" relative to a loose one. StarBind's scoring already gives tighter aspects more weight; widening the orb doesn't make a 7° trine count as much as a 1° trine. It just lets the 7° trine through the filter.

Synastry score centre

A related but separate knob: the synastry score centre is the midpoint of the compatibility score normalisation curve. The default of 40 is conservative. Together with the orb scale, the two knobs let you calibrate compatibility reads independently — orb scale controls what gets in, score centre controls how strict the grading curve is.

Practical guidance

• Start at 1.0.
• If the chart feels noisy, drop to 0.7 first, then 0.5 only if 0.7 is still too much.
• If the chart feels sparse, try 1.2 before going to 1.5.
• For a quick test of a relationship's strongest contacts only, drop to 0.5 — you'll get a short list of the closest aspects.
• For deep study of every possible connection, raise to 1.5 — but expect to do more interpretive filtering yourself.

Most practitioners settle on a personal preference between 0.7 and 1.0 after some experimentation. The default is conservative because conservative is the safest place to start; if you read enough charts you'll likely find your own sweet spot.