Synastry Chart
Type the birth details of two people. Times and places help, but the planets work with dates alone.
How synastry works
Synastry compares two birth charts by laying one over the other. Each planet of the first person is measured against each planet of the second, and any pair at a meaningful angle forms a cross-aspect. Astrologers read the pattern of these aspects as the chemistry between two people: where they spark, soothe or rub.
Some contacts get most of the attention. Sun to Moon, Venus to Mars and anything touching the other person's Moon are read as strong ties. A square or opposition is not bad in itself; tradition sees it as energy that needs handling. A trine or sextile is easy but can be taken for granted.
The result lists the closest aspects first, with the orb in degrees. Without birth times, the Moon may be off by several degrees, so treat its aspects with care.
What each cross-aspect means
| Aspect | Angle | Orb | Between two people |
|---|---|---|---|
| Conjunction | 0° | 8° | Merging: the two planets act as one |
| Sextile | 60° | 5° | Friendly support, easy talk |
| Square | 90° | 7° | Friction that keeps things alive |
| Trine | 120° | 7° | Natural understanding |
| Opposition | 180° | 8° | Attraction of opposites, balancing act |
Orbs are 2 degrees wider when the Sun or Moon is involved.
Worked examples
- 1990-03-05 New York and 1985-11-29 London: the closest cross-aspect is
Venus sextile Saturn - The same pair has this many cross-aspects in orb:
29 - 1983-05-25 Los Angeles and 1988-07-07 Tokyo: closest is
Moon opposition Jupiter
How this is calculated
Each person's Sun to Pluto from astronomy-engine at their own UTC birth instant. Every pair (A body, B body) is tested against the site's one aspect table: conjunction 8, sextile 5, square 7, trine 7, opposition 8 degrees, Sun and Moon plus 2. Sorted by orb.