What this calculator tells you
An aspect compares the angular separation of two planets with an enabled target angle. Calculate conjunctions, sextiles, squares, trines and oppositions among the seven traditional bodies, then inspect the actual difference and the allowed orb for each pair.
From two longitudes to an aspect
First take the shorter angular distance between the two longitudes. Compare it with 0°, 60°, 90°, 120° or 180°. The orb is the absolute difference from the target angle. A relationship appears only when that difference falls inside the allowed orb and the aspect type is enabled.
If unusually broad orbs make more than one enabled aspect qualify for a pair, this implementation selects the closest exact angle. It does not duplicate a pair under multiple aspect labels. Reduce orbs when you want to see only closer relationships.
| Aspect | Exact separation |
|---|---|
| Conjunction | 0° |
| Sextile | 60° |
| Square | 90° |
| Trine | 120° |
| Opposition | 180° |
Read the allowed orb and motion label
The form uses planetary moieties: allowed orb = (first planet’s orb + second planet’s orb) ÷ 2. With Sun 15° and Moon 12°, the allowed pair orb is 13.5°. These editable values define what is included; they are not uncertainty bounds on the astronomical positions.
Applying and separating are estimated from stored longitude speeds over a short 0.05-day step. They indicate whether the separation is locally moving toward or away from exactness. They do not establish an exact event time or a future outcome.
A CONCRETE EXAMPLE
A close Sun–Saturn trine in the stored example
The example includes a Sun–Saturn trine with orb 0.026731°. The default Sun orb is 15° and Saturn orb 9°, so their allowed orb is (15 + 9) ÷ 2 = 12°. The reported trine qualifies because 0.026731° is smaller than 12°. A broad allowed orb does not make every included aspect equally close.
This preserved, fictional example uses 1 January 2000, 12:00 UTC, Greenwich (51.4779° N, 0°), tropical zodiac and Alcabitius houses. Its stored source is Swiss Ephemeris 2.10.03. New calculations use Skyfield + JPL DE440; the historical example is not relabelled as a new calculation.
Read it in your own chart.
Keep the date, recorded time, location and zodiac visible as you compare results. Guest calculations need no account.
Use the calculator aboveCommon questions
Why is an aspect missing from my result?
Check whether its type is enabled, whether its actual separation is within the chosen orb, and whether both bodies are supported. This calculator uses Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn, without outer planets, nodes or angle aspects.
Is a sign-based trine always a calculated trine?
No. Sign relationships describe broad sectors. This calculator uses actual degree separation and the configured orb, so two planets in trine-related signs can still be outside the chosen tolerance.
Does this calculate synastry aspects?
No. These are relationships within one natal chart. The full chart also supports transits to natal positions for a selected moment, but it does not compare two people’s birth charts.
Calculation & interpretation
New personal calculations use Skyfield with JPL DE440 data and the site’s documented house and zodiac rules. The preserved Greenwich teaching chart has its own historical source label. Worked arithmetic and geometry examples are labelled separately. Astrological meanings are symbolic conventions, not established scientific predictions.
Birth time and place affect angles and houses. Unsupported or ambiguous inputs return an error rather than an invented chart. Personal results stay in browser state and do not create public result URLs.
- Skyfield: positions and coordinates
- NASA/JPL: planetary and lunar ephemerides
- IANA: time zone database